Acclimating Your Saltwater and Freshwater Fish – Float vs. Drip

Acclimating Your Saltwater and Freshwater Fish – Float vs. Drip
Author: Kara K.

Float Acclimation
The most commonly used method of acclimating freshwater and saltwater fish. This is when you float the bag that your fish has been placed in, in the water of your aquarium. Floating for approximately 30 minutes ensures that the temperature in the bag water slowly begins to match the temperature of your aquarium, making it less stressful on the fish. After floating for 15 minutes, double the volume of water in the bag with your aquarium water. Continue floating for another 10 minutes or so.

Just dumping them into the aquarium without acclimating is likely to cause enough shock to kill your new fish. After acclimating, the bag is opened or cut, and the fish is taken out of the bag with a net and released into it’s new home.

Pros: Temperature is most likely to cause shock in fish. The Float method ensures that the dangers of temperature change are eliminated.
Cons: Owners commonly will dump the bag water into their aquarium along with the new fish. If the water in your new fish’s bag is contaminated with whatever was in it’s previous aquarium, that bacteria will then be in yours.
Float acclimation

Drip Acclimation
Less heard of than the common float method. Drip acclimation requires:

1. A clean bowl large enough to hold your new fish and twice the water contents of its bag.
2. A net.
3. Air pump tubing.

With the tubing, create a siphon from your aquarium, into the clean bowl. Place the all contents of your new fish’s bag into the bowl. Siphon should drip 2-3 drops per second (a knot can be tied in it, and loosened/tightened to adjust the water flow) into the bowl. Let drip until the water in the bowl has doubled in volume. This process should take approximately 30-45 minutes, and definitely no longer than an hour. With a net, gently scoop your fish from underneath and place him into the aquarium.

Pros: Especially handy for saltwater fish because it gradually acclimates them to the salinity, pH, ammonia, nitrite, and nitrate levels in your established aquarium.
Cons: Temperatures in the low volume of water held in the bowl can drop considerably in half an hour, increasing the risk that your fish will suffer temperature change shock.

The endangered Lake Victoria cichlid (Haplochromis spp.)

The endangered Lake Victoria cichlid (Haplochromis spp.) is found only in the Lake Victoria basin, the most important freshwater fishery in Africa.

The greatest threats affecting the Lake Victoria cichlid are human-related and include pressures from the introduced Nile perch, pollution, and algae build-up.  These factors are causing cichlid species to go extinct before scientists can even name them all.  Biologists believe that 300 of the possible 500 cichlid species native to Lake Victoria have already gone extinct.

The AZA Freshwater Fish Taxon Advisory Group and the Lake Victoria Cichlids Species Survival Plan® Program manage over 2,800 cichlids representing 13 different species at 15 AZA-accredited aquariums.   These institutions have created a collaborative breeding program that strives to preserve many cichlid species for the future.

The AZA Conservation Endowment Fund has provided over $15,000 to the Toronto Zoo, New England Aquarium, and Columbus Zoo and Aquarium for their conservation and education work with the local National Museums of Kenya and the Fisheries Resources & Research Institute (FIRI) in Uganda. The goal of the FIRI is to implement conservation methods for cichlid biodiversity in the region by developing aquariums and pond aquaculture for breeding purposes, to educate the local population about the issues affecting these species, and to urge local fishermen to throw back fish that are too small to eat in hopes of building a sustainable population for the future.

Lake Victoria Cichlid Facts

Status Endangered
Size Their color may vary.  Males are generally brightly colored, while females are more muted in color.
Appearence Cichlids are only found in the Lake Victoria Basin of Africa, which includes the countries of Tanzania, Uganda and Kenya.
Habitat Cichlids are only found in the Lake Victoria Basin of Africa, which includes the countries of Tanzania, Uganda and Kenya.
Diet Their diet differs between species, but cichlids eat algae, plants, snails, crustaceans, other fish and even members of their own species.
Breeding Cichlids are “mouth brooders,” which means eggs and wrigglers develop in the female’s mouth and can number from 10 to 80 wrigglers!

Most Common Mistakes Made by Saltwater Aquarium Keepers

Most Common Mistakes Made by Saltwater Aquarium Keepers

By Stan & Debbie Hauter, Guide

No matter what kind of aquarium keeper you are, here is a list of the most common mistakes you may be making. These problems can be avoided if you’re aware of them before you start an aquarium.

Overfeeding Fish and Invertebrtes

Uneaten food just lays on the bottom of the tank, creating nitrates and overloading the biological filter.
Not fully understanding the nutritional requirements of their fish, the tendency of many people is to “throw food” at fish in order to fulfill their requirements. If the fish are not accepting the food offered, many aquarists will “throw even more” at the fish, thinking that the fish just isn’t seeing the food. Feed once, twice per day, or once every 2 or 3 days? How Often Should I Feed My Fish? helps you understand a fish’s requirements.

Know what is in the food you are feeding by comparing the nutrients in commercial foods, purchase only high quality foods and feed only what your fish will consume in 2-3 minutes per feeding.

Moving Too Fast

“Patience” is a requirement with just about anything that you do with a saltwater aquarium. Far too many people report problems after they have put a tank together, because they are just moving too fast! Far too often we have read aquarists comments like, “I need test kits? What for, and what kind?” Of course this is after they have had a tank for some time. A high percentage of people do not take the time to read and study up on the hobby before getting started.

Overloading the System

A problem that goes hand-in-hand with moving too fast is craming too much livestock and/or live rock into the aquarium all at once, especially in a tank that is not fully cycled, or has just completed the cycling process. Even in a well established system, placing too many new additions into the tank to quickly can cause new tank syndrome. Slow down! Saltwater aquarium keeping is not a timed event, so take it easy, and work on your patience skills.

Inadequate Filtration and Water Circulation

Having sufficient biological filtration is a primary key to success in keeping a saltwater aquarium. There are a number of filtration methods to choose from, but not making the right filter selection for the bio-load planned for your tank can lead to a wide variety of problems. Whether it be biological, mechanical, or chemical, it’s better to have more, rather than too little filtration.

This same concept applies to circulation of the water in the aquarium as well. The lack of good water flow throughout the system can lead to problems with low DO (dissolved oxygen), the build up of slime or other types of nuisance algae, prevention of stationary animals receiving food, and more. The solution here? Add a powerhead or two, or a surge device.

Misdiagnosing Diseases

When it comes to diagnosing diseases, saltwater ich is the biggest problem. It is easy to confuse Oodinium (Amyloodinium ocellatum – a.k.a. Marine Velvet or Coral Fish Disease) with White Spot Disease (Cryptocaryon irritans). They are similar but two quite different types of saltwater ich, and each responds to different types of treatment. It is important to properly diagnose and treat these parasites, as well as other diseases.


Way too often one or more remedies are just thrown at a sick or ailing fish without knowing what the problem is. Medications should only be used when necessary, and whenever possible in a quarantine tank. The most important factor with medications is to use one that is formulated to “target” the specific disease or diseases you are dealing with.

Purchasing Animals Without Knowing Anything About Them

It never ceases to amaze us how often people select new additions for their aquarium without knowing what the animals are, how to care for and feed them. Before purchasing anything, take the time to obtain information about it first. You shouldn’t buy on impulse because you like the pretty colors a fish has, how cute or stunning it looks, or for any other “touchy-feely” reason, or if a sales person can’t provide you with critical information you need to know about a particular animal.

Livestock Incompatibility

Statements like my wrasse ate my hermit crab, my tangs just won’t get along, and similar ones are all too frequently heard. Purchasing livestock without knowing whether or not they will peacefully reside with other tankmates can lead to dead or injured animals, as well as stress related diseases. Use common sense and learn about the compatibility of animals you are considering for your aquarium, before putting them together!

Purchasing Animals in Poor Health

One of the easiest things to do when selecting a critter is to determine whether or not it is healthy. In a simple phrase, most sick fish don’t eat. Before purchasing a fish or other animal, it is best to have a sale’s person in a store show you that it is in fact eating. On your part, learn how to recognize the symptoms or outward signs of common illnesses so you know what to look for when inspecting livestock to buy.

Using a Poor Quality Fresh Water Source

Although many aquarists do so, choosing to use water straight from the tap or unpurified water of another source to make up saltwater solutions and to top off a tank can lead to many water quality issues in aquariums. Using a water purification filter, buying clean natural sea water, or prefiltered RO/DI water from a reliable supplier is an investment that will pay for itself in the long run.

Lack of Proper Tank Maintenance

Well-maintained saltwater systems seldom experience high nitrate, bacterial outbreaks, or other water quality issues. To avoid the usual pitfalls with problems in this area of aquaria keeping, set up and follow a regular maintenance routine.

Will Algae be a problem in my saltwater reef aquarium?

You should not have a problem with algae if you have followed these recommendations:

  • Purify your tap water with a triple carbon prefilter and reverse osmosis or deionizer system;
  • Use Kalkwasser regularly to keep the pH between 8.2 and 8.4;
  • Do water changes every 2 to 3 weeks;
  • With water changes, vacuum off as much as possible of the debris in the rock crevices;
  • Change your prefilter pad every week;
  • Have the lighting on for no more than 9 hours a day, using the wattage recommended
  • Do not use unnecessary additives
  • Employ herbivorous livestock (turbo snails, small hermit crabs, hard star fish, and algae-eating fish such as yellow tangs, blennies, angels, etc.).

By following the recommendations here, you should be able to manage the micro-algae in your tank. These procedures will ensure that your reef will not be overtaken by green, brown, or red algae that would cover desirable livestock and organisms (such as the hard pink coralline algae) that depend on water flow and light.

I cannot overemphasize the importance of following all the previous recommendations, as they will ensure that the undesirable algae do not have the conditions they need to survive, and undesirable algae are the scourge of reef keeping. Follow the suggested procedures, and the algae should be manageable!

Micro-algae will grow!

The growth of micro-algae is a natural occurrence and will happen in most healthy tanks. It is only when the algae become unmanageable that we have a problem. Managing the growth of micro-algae means (1) limiting the conditions they need to thrive, (2) having livestock that will eat most of the algae, and (3) removing the remainder by hand with magnets, blade scrapers, and brushes.

In my tanks, brown and some green algae form on the glass on a regular basis. They do not thrive for long in other areas; they are only a problem on the glass and overflow pipes.

The glass is easily cleaned with an algae glass-cleaning magnet. When buying such a magnet, purchase the largest one you can find. Usually the larger the size, the stronger the magnet and the better the cleaning capabilities (pull) it will have. The magnet does a nice job for weekly or twice-weekly cleaning. Little bright green patches will eventually form. These should be scraped off with a razor blade. You should only have to “blade” the glass about once a month at the most.


Keep in mind that algae will grow and will have to be removed by hand on a regular basis. Do not be deceived when you go into your favorite reef store and observe that their tanks have no visible algae. You may think, “My tank has algae, why doesn’t his?” The fact is that every morning someone cleans the glass and maintains the tanks so they will look absolutely pristine. This gives the impression that the people in the store know something about water quality that you don’t. In fact, all they are doing is daily maintenance, in addition to the procedures listed above.

Then of course, the remaining algae will be removed by hand, particularly from the glass and overflow pipes. By using a strong magnet or a razor blade for the glass, and a bottle brush for the overflow, it is not a problem to remove undesirable algae.

It is important to remember that we want to remove the algae, not just dislodge it. When using the magnet, after a few swipes you will feel the scrubber part of the magnet cleaner getting full of algae. Take this to the sink and rinse it off. Resume cleaning and repeat the rinsing process as often as needed. Rinse the scrubber when you are done. When using the bottle brush, swirl it to trap the algae in the bristles, and rinse it out in the sink.

A strong algae magnet and bottle brush are useful tools. Some algae, of course, will get away from you. This cannot be avoided. Remove as much as you can, within reason. Algae that are dislodged and left in the tank will either reattach elsewhere, decompose into food for other algae, or get trapped in the prefilter.

Summary of algae management:

If you follow the suggestions I have given, it can be done easily. Algae accumulation can be a serious threat to the enclosed reef system. Left unmanaged, it can become a problem that would test anyone’s patience and sanity; it is not something you want to battle with! However, if you select your livestock carefully and follow the other recommendations I have discussed, the naturally-occurring algae in your tank will be a good food source for the livestock, and what they don’t eat can be managed with regular maintenance.

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Should I Keep My Betta in a Vase?

By Shirlie Sharp

The Peace Lily Vase-Siamese Fighting fish combination has sparked more debate than almost any other aquarium topic. The pivotal question is if it’s safe for the fish. What is my stand on the issue? I do not consider a flower vase a healthy environment for a Betta (aka: Siamese Fighting fish) for a number of reasons.

Rice Paddy Argument
The argument made for keeping a Betta in a vase is that pumps, filters, and other aquarium equipment, do not exist in nature. By putting the fish in what appears to be a natural environment the assumption is made that it is inherently healthier than an aquarium. That simply isn’t the case.

It is true that in nature the Betta lives in shallow rice paddies and swamps. However, those waters represent a complete ecological system that a small vase cannot replicate. Those seemingly small rice paddies are actually part of a much larger body of water that dilutes toxins. Scavengers and bacteria present in the water break down wastes and render them harmless to fish living there.

Betta Diet
The water volume isn’t the only problem with a vase. In nature, the Betta Betta lives on a diet that consists predominantly of insects and insect larvae. In fact, Bettas are valued for their role in controlling mosquitoes in their native habitat. The Betta’s digestive tract is built to digest meat, rather than vegetable material. Its upturned mouth is designed to grab insects that have fallen into the water.

A diet consisting of vegetable matter may keep a Betta alive for a while, but it is neither natural nor healthy. Over time, the Betta will slowly be starved of the proper nutrients and more easily fall victim to disease.

Water Temperature
Water temperature in the Lily-Betta combination is another problem. The primary reason a Betta in a small bowl is often listless is due to low water temperature. The Siamese Fighting fish is native to countries such as Thailand, where the climate is hot and moist. The ideal water temperature for the Betta is about 80 degrees Fahrenheit.

Without a heater, the water in a vase will be too cool for comfort most of the time. Although the Betta can survive at lower temperatures, when the water is too chilly they become lethargic and may even refuse to eat.

Betta Breathing
Lastly, there is the issue of how the Betta breathes. Like other fish, the Betta taakes in oxygen from the water. However, the Betta also has a special organ that allows it to breathe air directly from the surface of the water. This organ is what allows the Betta to live in water that has very little oxygen.

Studies have shown that fish with this organ must regularly breathe some air at the surface, even if there is sufficient oxygen in the water itself. Unfortunately, for the Betta, if the Lily vase is not set up with an open space at the top of the water, the Betta may become deprived of the oxygen it needs to survive.

The Peace Lily Vase-Siamese Fighting combination has persisted as a popular fad, but it is neither natural nor healthy for the fish. A dog or cat owner would not shut their pet in a small closet with minimal heat, food, and air. Should fish be treated any less humanely?

How to diagnose and treat Nitrite Poisoning

Nitrite Poisoning

Disease Type: Environmental

Nitrite poisoning follows closely on the heels of ammonia as a killer of aquarium fish. Just when you think you are home free after losing half your fish to ammonia poisoning, the nitrites rise and put your fish at risk again. Anytime ammonia levels are elevated, it is a safe bet that elevated nitrites will soon follow. To avoid nitrite poisoning, test when settng up a new tank, in established tanks when adding new fish, when the filter fails due to power or mechanical failure, and when treating sick fish with medications.


  • Fish gasp for breath at the water surface
  • Fish hang near water outlets
  • Fish is listless
  • Tan or brown gills
  • Rapid gill movementAlso known as ‘brown blood disease’ because the blood turns brown from a increase of methemoglobin. However, methemoglobin causes a more serious problem than changing the color of the blood. It renders the blood unable to carry oxygen, and the fish can literally suffocate even though there is ample oxygen present in the water. Different species of fish tolerate differing levels of nitrite. Some fish may simply be listless, while others may die suddenly with no obvious signs of illness. Common symptoms include gasping at the surface of the water, hanging near water outlets, rapid gill movement, and a change in gill color from tan to dark brown. Fish that are exposed to even low levels of nitrite for long periods of time suffer damage to their immune system and are prone to secondary diseases, such as ich, fin rot, and bacterial infections. As methemoglobin levels increase damage occurs to the liver, gills and blood cells. If untreated, affected fish eventually die from lack of oxygen, and/or secondary diseases.
  • Treatment
  • Large water change
  • Add salt, preferably chlorine salt
  • Reduce feeding
  • Increase aerationThe addition of one half oz of salt per gallon of water will prevent methemoglobin from building up. Chlorine salt is preferable, however any aquarium salt is better than no salt at all. Aeration should be increased to provide ample oxygen saturation in the water. Feedings should be reduced and no new fish should be added until the tank until the ammonia and nitrite levels have fallen to zero. Nitrite is letal at much lower levels than ammonia. Therefore it is critical to continue daily testing and treatment until the nitrite falls to zero.
  • Prevention
  • Stock new tanks slowly
  • Feed sparingly and remove uneaten food
  • Change water regularly
  • Test water regularly to catch problems earlyThe key to elminating fish death is to avoid extreme spikes and prolonged elevation of nitrites. When starting a new tank, add only a couple of fish initially and do not add more until the tank is completely cycled. In an established tank, only add a couple of new fish at a time and avoid overstocking. Feed fish small quantities of foods, and remove any food not consumed in five minutes. Clean the tank weekly, taking care to remove an dead plants or other debris. Perform a partial water change at least every other week, more often in small heavily stocked tanks. Test the water for nitrite after an ammonia spike has occured as there will be a nitrite increase later.
  • Shirlie Sharpe

    Fish School

    What about Filters (aquarium)

    Filter (aquarium)

    From Wikipedia, the free encyclopedia

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    an air-driven corner filter

    Aquarium filters are critical components of both freshwater and marine aquaria.[1][2][3] Aquarium filters remove physical and soluble chemical waste products from aquaria simplifying maintenance. Furthermore, aquarium filters are necessary to support life as aquaria are relatively small, closed volumes of water compared to the natural environment of most fish.[4]



    [edit] Overview

    Animals, typically fish, kept in fish tanks produce waste from excrement and respiration. Another source of waste is uneaten food or plants and fish which have died. These waste products collect in the tanks and contaminate the water. As the degree of contamination rises, the risk to the health of the aquaria increases and removal of the contamination becomes critical. Filtration is a common method used for maintenance of healthy aquaria.

    [edit] Biological filtration and the nitrogen cycle

    A large Koi Pond trickle biological filter designed to maximize beneficial effects of the nitrogen cycle.

    Proper management of the nitrogen cycle is a vital element of a successful aquarium. Excretia and other decomposing organic matter produce ammonia which is highly toxic to fish. Bacterial processes oxidize this ammonia into the slightly less toxic nitrites, and these are in turn oxidized to form the much less toxic nitrates. In the natural environment these nitrates are subsequently taken up by plants as fertilizer and this does indeed happen to some extent in an aquarium planted with real plants.

    An aquarium is, however, an imperfect microcosm of the natural world. Aquariums are usually much more densely stocked with fish than the natural environment. This increases the amount of ammonia produced in the relatively small volume of the aquarium. The bacteria responsible for breaking down the ammonia colonize the surface of any objects inside the aquarium. A biological filter is nothing more than a chemically inert porous sponge, which provides a greatly enlarged surface area on which these bacteria can develop. These bacterial colonies take several weeks to form, during which time the aquarium is vulnerable to a condition commonly known as “new tank syndrome” if stocked with fish too quickly. Accumulation of toxic ammonia from decomposing wastes is the largest cause of fish mortality in new, poorly maintained or overloaded aquariums.[5] In the artificial environment of the aquarium, the nitrogen cycle effectively ends with the production of nitrates. In order that the nitrate level does not build up to a harmful level regular partial water changes are required to remove the nitrates and introduce new, uncontaminated water.

    [edit] Mechanical and chemical filtration

    The process of mechanical filtration removes particulate material from the water column. This particulate matter may include uneaten food, faeces or plant or algal debris. Mechanical filtration is typically achieved by passing water through materials which act as a sieve, physically trapping the particulate matter.[1] Removal of solid waste can be as simple as physical hand netting of debris, and/or involve highly complex equipment. All removal of solid wastes involve filtering water through some form of mesh in a process known as mechanical filtration. The solid wastes are first collected, and then must be physically removed from the aquarium system. Mechanical filtration is ultimately ineffective if the solid wastes are not removed from the filter, and are allowed to decay and dissolve in the water.

    Dissolved wastes are more difficult to remove from the water. Several techniques, collectively known as chemical filtration, are used for the removal of dissolved wastes, the most popular being the use of activated carbon and foam fractionation. To a certain extent, healthy plants extract dissolved chemical wastes from water when they grow, so plants can serve a role in the containment of dissolved wastes.

    A final and less common situation requiring filtration involves the desire to sterilize water born pathogens. This sterilization is accomplished by passing aquarium water through filtration devices which expose the water to high intensity ultraviolet light and/or exposing the water to dissolved ozone gas.

    [edit] Materials suitable for aquarium filtration

    Sponges, plastic balls, ceramic tubes and gravel are all suitable for aquarium filtration

    Numerous materials are suitable as aquarium filtration media. These include synthetic wools, known in the aquarium hobby as filter wool, made of polyethylene terephthalate or nylon. Synthetic sponges or foams, various ceramic and sintered glass and silicon products along with igneous gravels are also used as mechanical filter materials. Materials with a greater surface area provide both mechanical and biological filtration. Some filter materials, such as plastic “bioballs”, are best used for biological filtration.

    With the notable exception of diatom filters, aquarium filters are rarely purely mechanical in action, as bacteria will colonise most filter materials effecting some degree of biological filtration.[1] Activated carbon and zeolites are also frequently added to aquarium filters. These highly porous materials act as adsorbates binding various chemicals to their large external surfaces[2] and also as sites of bacterial colonisation.

    The simplest type of aquarium filter consists only of filter wool and activated carbon. The filter wool traps large debris and particles, and the activated carbon adsorbs smaller impurities. These should be changed regularly at suitable intervals[6]. This is particularly important in the case of activated carbon filters, which may re-release their adsorbed contents in large (and therefore harmful) doses if they are allowed to saturate. [7]

    [edit] Types of aquarium filters

    A commercially available canister filter

    Numerous types of aquarium filters are commercially available,[8] including:

    [edit] External filters

    A schematic diagramme of the function of the canister filter

    External filters remove water from the aquarium which is then pushed (or pulled) through a series of different levels filter media and returned to the aquarium.[1] They are usually more effective and easier to maintain than internal filters.[9]

    [edit] Canister filters

    Compared to filters that hang on the back of the aquarium, canister-style external filters offer a greater quantity of filter materials to be used along with a greater degree of flexibility with respect to filter material choice.[2] Water enters the canister filled with the chosen filter material through an intake pipe at the bottom of the canister, passes through the material, and is pumped back to the aquarium through an electric pump on the top of the canister.[9] Benefits of this type of filter are that they can provide a high volume of filter material without reducing the internal space in the aquarium, and that they can be disconnected from the tank for cleaning/maintenance and replaced without disturbing the aquarium interior or occupants. Disadvantages of canister filters include the increased cost and complexity relative to internal filters and difficulties in cleaning the tubes which transfer water to and from the aquarium.[3] There’s also the risk of a leak, which naturally is an issue for any filter placed outside of the aquarium.

    [edit] Diatom filters

    Diatom filters are used only for sporadic cleaning of tanks, they are not continuously operated on aquariums. These filters utilise diatomaceous earth to create an extremely fine filter down to 1 µm which removes particulate matter from the water column.[1]

    [edit] Trickle filters

    Trickle filters, also known as wet/dry filters are another water filtration systems for marine and freshwater aquariums.[9] This filter comes in two configurations, one which is placed on top of the aquarium (more rarely seen) and one which is placed below the aquarium (more common).

    If the wet/dry filter is placed on top of the aquarium, water is pumped over a number of perforated trays containing filter wool or some other filter material. The water trickles through the trays, keeping the filter wool wet but not completely submerged, allowing aerobic bacteria to grow and aiding biological filtration. The water returns to the aquarium like rain.[9]

    Alternatively, the wet/dry filter may be placed below the tank. In this design, water is fed by gravity to the filter below the aquarium. Prefiltered water is delivered to a perforated plate (drip plate). Prefiltering may take place in the aquarium via a foam block or sleeve in the overflow, or weir siphon, or it may be prefiltered by filter wool resting on the perforated plate. The waste laden water from the aquarium spreads over the drip plate, and rains down through a medium. This may be a filter wool/plastic grid rolled into a circular shape (DLS or “Double Layer Spiral”) or any number of plastic media commonly known as Bio Balls. As the water cascades over the media, CO2 is given off, oxygen is picked up, and bacteria convert the waste from the tank into less harmful materials. From here the water enters the sump. The sump may contain a number of compartments, each with its own filtration material. Often, heaters and thermostats are placed in the sump.[9]

    [edit] Baffle filters

    A new baffle filter, under a large volume, cichlid aquarium

    Baffle filters are similar to wet and dry, trickle filters in that they are generally situated below the aquarium. This type of filter consists of a series of baffles that the water must pass through in order to reach the pump which is returning water to the aquarium. These baffles then act much like a series of canister filters and can be filled with different filter media for different purposes.[10].

    [edit] Internal filters

    An internal aquarium filter driven by air displacement

    Internal filters are, by definition, filters within the confines of the aquarium. These include the sponge filter, variations on the corner filter (pictured top right and left), foam cartridge filter and the undergravel filter.[1] An internal filter may have an electric pump and thus be an internal power filter, often attached to the inside of aquaria via suction cups.

    [edit] Airlift filters

    Sponge filters and corner filters (sometimes called box filters) work by essentially the same mechanism as an internal filter. Both generally work by airlift, using bubbles from an air pump rising in a tube to create flow. In a sponge filter, the inlet may only be covered by a simple open-cell block of foam. A corner filter is slightly more complex. These filters are oftenplaced in the corner on the bottom of the aquarium. Water enters slits in the box, passes through a layer of medium, then exits through the airlift tube to return to the aquarium. These filters tend to only be suitable for small and lightly-stocked aquaria. The sponge filter is especially useful for rearing fry where the sponge prevents the small fish from entering the filter.[9]

    [edit] Undergravel filters

    A schematic diagramme of an undergravel filter run by both an air displacement and water pump (powerhead)

    Undergravel filters consist of a porous plate which is placed beneath the gravel on the base of the aquarium and one, or more, uplift tubes. Historically, undergravel filters have been driven via air displacement. Air stones are placed at the base of uplift tubes which force water out of the uplift tube creating negative pressure beneath the undergravel filter plate. Water then percolates down through the gravel which itself is the filtration material.[1] Greater flow rate of water through the gravel can be achieved via the use of water pump rather than air displacement.[1]

    Beneficial bacteria colonize the gravel bed and provide biological filtration, using the substrate of the aquarium itself as a biological filter.[6][9]

    Undergravel filters can be detrimental to the health of aquatic plants.[6] Fine substrates such as sand or peat may clog an undergravel filter.[9] Undergravel filters are not effective if the substrate bed is uneven. In an uneven gravel bed, water will flow only through the thin portions of the bed, leaving the more heavily covered areas to become anoxic. Because of this, animals that dig, such as cichlids, are best kept in an aquarium using some other type of filtration.[citation needed]

    [edit] Submersible pumps/filters

    or circulation pumps

    Wiki letter w.svg
    Please help improve this article by expanding it. Further information might be found on the talk page. (October 2007)

    [edit] Marine-specific systems

    Marine aquaria have specialised needs and requirements, to this end the filtration of the marine aquarium is often more complex than freshwater aquariums.

    [edit] Protein Skimmers

    Main article: Protein skimmer

    Protein skimmers are filters used to fractionate and remove various dissolved organic contaminates typically from marine aquariums. The technique uses the chemical polarity of proteins and amino acids to remove the compounds in the foam produced by the filter. As very fine air bubbles are introduced into the fractionating column, the organic compounds attach to the bubbles. The air bubbles rise, and collect at the top of the Protein Skimmer, coagulating into a stiffer foam. The foam eventually builds up and overflows into a collection cup for complete removal. This is beneficial because the contaminates are removed from the system prior to decomposition into more toxic compounds. Protein skimmers are often used in combination with other filtration devices in marine aquarium setups.

    [edit] Deep sand beds

    Main article: Deep sand bed

    Deep sand beds filtration is a technique designed to use anaerobic microbes to degrade nitrate to gaseous nitrogen.

    [edit] Berlin method

    Main article: Berlin Method

    The Berlin method of marine tank filtration is similar to the deep sand bed filtration technique in that relies on the action of anaerobic bacteria in the outer layers of porous rocks to degrade nitrate to gaseous nitrogen.


    1. ^ a b c d e f g h Riehl, Rüdiger. Editor.; Baensch, HA (1996. 5th Edn.). Aquarium Atlas. Germany: Tetra Press. ISBN 3-88244-050-3.
    2. ^ a b c Leibel WS (1993) A fishkeepers guide to South American cichlids. Tetra Press. Belgium pg 12-14.
    3. ^ a b Loiselle, Paul V. (1995). The Cichlid Aquarium. Germany: Tetra Press. ISBN 1-56465-146-0.
    4. ^ Sands D (1994) A fishkeepers guide to Central American cichlids. Tetra Press. Belgium pg 17-19.
    5. ^ Patrick T. K. Woo; David W. Bruno (2002). Diseases and disorders of finfish in cage culture. Wallingford, Oxon, UK: CABI Pub. pp. 284. ISBN 0-85199-443-1.
    6. ^ a b c Axelrod, Herbert, R. (1996). Exotic Tropical Fishes. T.F.H. Publications.. ISBN 0-87666-543-1.
    7. ^ Eade, Andrew (1999). Coldwater Fishkeeping. Ringpress Books. pp. 33. ISBN 1-86054-072-4.
    8. ^ Mary Bailey; Nick Dakin (2001). The Aquarium Fish Handbook. New Holland Publishers. pp. 26. ISBN 9781859741900.
    9. ^ a b c d e f g h Sanford, Gina (1999). Aquarium Owner’s Guide. New York: DK Publishing. pp. 164–167. ISBN 0-7894-4614-6.
    10. ^ Sandford G, Crow R (1991) The Manual of Tank Busters. Tetra Press, USA

    Bigfin Squid In Kona Hawaii

    Bigfin Squid in Kona Hawaii from Steve on Vimeo.

    Beginner Fish

    Good (and Bad) Beginner Fish



    contributed by Dean Hougen

    This article considers fish choices for the beginning aquarist, covering good choices for the complete novice (“Good First Fish”), good choices for the near novice who wishes to expand his or her options for new fish (“Good Second Fish”), and poor choices for beginning aquarists (“Bad First Fish”).


    The FAQs owe their existence to the contributors of the net, and as such it belongs to the readers of rec.aquaria and alt.aquaria. Articles with attributions are copyrighted by their original authors. Copies of the FAQs can be made freely, as long as it is distributed at no charge, and the disclaimers and the copyright notice are included.



    Since even a small amount of material can be difficult for a newcomer in any field to digest and retain, the novice aquarist may wish to read only the “Good First Fish” section to begin with. Then, while consulting a good beginner’s book (the most essential item for any novice aquarist to own), she or he should choose a small number of possibilities for the fish with which to start her or his new tank.

    If someone familiar with the local fish stores is available, it is wise to get a recommendation for where to shop for fish. Otherwise the beginner should try looking for shops that specialize in fish, either exclusively or as a major part of their business. This is no guarantee, of course, but it does improve the odds of finding a good store.

    If, upon reaching the store, none of the selected fish can be found, the novice should refrain from purchasing any fish that he or she is unfamiliar with, even if recommended by the store’s employees. (Some stores have very knowledgeable staffs but many, alas, do not. It will take some time before the new fishkeeper can discern a good store from a bad one, or good advice from poor.) At this point, another store could be sought out or further reading done to determine alternate choices for first fish.

    Assuming that desirable choices for first fish can be found, the beginner should carefully inspect the specimens for sunken bellies, sunken eyes, clamped fins, labored breathing (often with gill covers quite extended), and any sort of external blemishes that might indicate parasites or disease. If the fish appear healthy, the novice should ask to purchase a very small number of fish, depending on the size of the tank and the fish. A twenty gallon tank is a good size for a beginner; it is large enough that the water conditions will be fairly stable, yet small enough that the beginner is not intimidated. For this size tank a single fish of one to two inches in length, or three or four smaller fish, is the most the novice should start with. (If more fish are put into the tank initially, poisonous ammonia will build up and kill the fish. If the tank population is built up gradually, however, this will not be a problem. To understand this gradual introduction of fish, known as `cycling the tank’, the novice should read about the nitrogen cycle in his or her aquarium book, or the NITROGEN CYCLE section of the BEGINNER FAQ.)

    Good First Fish

    If we define a good beginner’s fish as one that is easy to feed and care for, hardy, able to live in a variety of water conditions, and attractive, then there are a number of widely available fish which fit the bill nicely. Many of these are regularly sold as beginner’s fish. But watch out! Many of the fish sold as beginner’s fish really are not well suited to that role.

    Many of the smaller schooling fish make ideal first fish. These include White Cloud Mountain Minnows, the several commonly available species of Danios and Rasboras, and most available species of Barbs. For those with a slightly larger tank, Rainbowfish make a great schooling fish. Corydoras Catfish are ever popular schooling catfish.

    While many beginners are tempted to get just one or two of each of several different schooling fish, this should be resisted. Schooling fish do better if there are several of their own species present for them to interact with. A minimum of six of each of the midwater schooling fish is recommended, while four is the bare minimum for Corys. In the long run, a school of a dozen fish showing their natural behavior will be more pleasing than a mixed group of fishes unhappily forced to share the same tank. (“Mom, why is that one fish hiding behind the heater and that other one just hanging in the corner?”)

    Of course, as mentioned in the introduction, the population needs to be built up slowly, two or three fish at a time. The aquarist might, for instance, build up a school of eight Rasboras of a certain species, then turn to building up a school of six of a species of Cory Cats.

    Some Cyprinids

    White Clouds, Danios, Rasboras, and Barbs are all Asian fish related to the Carp and the Minnow. All of these fish belong to the family Cyprinidae. White Clouds, Danios, Rasboras, and Barbs are small, active, hardy, and colorful.

    “White Cloud Mountain Minnows” – Tanichthys albonubes
    Found in mountain streams in China, White Clouds can be kept in unheated tanks (down to 55F). Some people advise against putting these fish in tropical tanks but I have found that they do fine in heated aquaria as well, as long as the temperature is not kept above the mid 70s. They can be fed any small food and they spawn often but fry will not be seen unless the parents are removed to another tank. White Clouds are brown with a red tail and a silvery white line down the side that shines in the light. They get to be 1 1/2″ long.
    Several species of Danios are often found in pet stores, including the Giant Danio – Danio aequipinnatus, the Zebra Danio – Brachydanio rerio, the Leopard Danio – Brachydanio frankei, and the Pearl Danio – Brachydanio albolineatus. These fish are fast swimmers and are always in motion. Different patterns of blue markings allows one to tell these fish apart. Most Danios stay under 2 1/2″ long, although Giant Danios can get up to 4″.
    The most popular Rasbora is the Harlequin Rasbora – Rasbora heteromorpha. A very similar looking species, Rasbora espei, is also available, as is the Clown Rasbora – Rasbora kalochroma and the Scissor-Tail Rasbora – Rasbora trilineata. Orange, brown, and red are usual colors for Rasboras, and their stop-and-start swimming makes them interesting to watch as a school. Scissor-Tails can get up to 6″ long and Clown Rasboras up to 4″ while Harlequins stay under 2″ long.
    By far the most commonly seen and commonly cursed Barb is the Tiger Barb – Capoeta tetrazona. It nips the fins of other fish if not kept in a large school of its own species and because it is over-bred it is susceptible to diseases. Several aquarium morphs are also available (such as the greenish “Mossy Barb” and an albino variety) but these are even more sickly and often deformed.Don’t give up on the Barbs too fast though, as many are well suited as first fish, especially for those with moderate sized tanks. Capoeta titteya, the Cherry Barb, is a terrific little barb – up to 2″ long and with a wonderful orange-red color. Mid-sized barbs (up to about 4 1/2″ long) include Clown Barbs – Barbodes everetti, Rosy Barbs – Puntius conchonius, and Black Ruby Barbs – Puntius nigrofasciatus. The artificial morphs (long-finned, albino, etc.) of the Rosy Barb should be avoided though, as these tend to be sickly. Checker Barbs – Capoeta oligolepis and Spanner or T-Barbs – Barbodes lateristriga are large, peaceful barbs (Spanner Barbs up to 7″ long). Unless you have a very large aquarium avoid Tinfoil Barbs – Barbodes schwanefeldi. They grow to be over a foot long!

    Note that many barbs don’t school as “nicely” as do Danios or Rasboras, but most should be kept in schools nonetheless. Also note that many authors may put all of the above mentioned species in the genus Barbus.

    Corydoras Catfish

    Cory Cats are members of the family Callichthyidae, a family of armored catfish from South America. Corys are small (generally 2 1/2″ long or less), schooling fish that are always searching the bottom of the tank for food. There are at least 140 species of catfish in the genus Corydoras. Some of these are quite delicate and die quickly even in the hands of experts. The fragile ones, however, are rarely seen in pet stores and are high priced when they can be found. The Corys you will see for reasonable prices are hardy and can even survive in a tank with low oxygen as they can swallow air from the surface and absorb it through their intestines. Some Corys you may encounter are the Bronze Cory – C. aeneus, the Spotted Cory – C. ambiacus, the Leopard Cory – C. julii, the Skunk Cory – C. arcuatus, the Bandit Cory – C. metae, and the Panda Cory – C. panda.

    Corys generally feed at the bottom of the tank and special sinking foods should be fed. These include sinking pellets like Tabi-Min and frozen blood- worms. Care should be taken to insure that all frozen foods are eaten quickly as they decay rapidly and can foul the tank. Don’t overfeed!


    Rainbows are extremely colorful fishes native to Australia, New Guinea, and Madagascar. Like the Cyprinids described above, Rainbows are schooling fish and should be kept in groups of six or more. Larger, somewhat more expensive, and harder to find than many of the schooling fishes already discussed, Rainbows are easily cared for, active, and make good first fish for those who want to try something a little less common. Look in your dealer’s tanks for the Australian Rainbow – Melanotaenia splendida, Boeseman’s Rainbowfish – M. boesemani, Turquoise Rainbows – M. lacustris, and the Celebes Rainbow – Telmatherina ladigesi


    Good Second Fish

    The previous section talked about good fish for the complete novice aquarist. This section will discuss good fish for beginning aquarists who have had some experience or who are willing to do more careful research and shopping before buying their fish.

    Many of the fish recommended here are every bit as hardy, adaptable, and easy to care for as those in the first section. However, in the first section I was able to recommend whole groups of fish or at least say to watch out for only a species or two in each group as bad choices. Here, however, the groups will be quite mixed with many good choices and many poor ones. Also, some of the fish in this section are hardy only if some special needs are cared for. If you wish to successfully keep fish from these groups you need to be sure you know which species you are getting and what their needs are.

    Why bother? If you are a complete novice, perhaps you shouldn’t. The great choices from the “First Fish” list should allow you to get your feet wet (as it were) with minimum risk. However, as you gain experience you may decide to give some of these fish a try. Many are quite beautiful and/or have interesting behaviors and some aquarists become so taken with them that they join specialist clubs just to learn about and trade one group or another of these fish.


    Loaches are long-bodied Asian fishes distantly related to the Cyprinids (Barbs, Danios, etc.) described above. Like Cory Cats, loaches have a down-turned mouth equipped with barbels – an adaptation for living and feeding at the bottom of ponds and streams. They will scavenge the tank bottom eating the food missed by other fishes, but you should take care to see that they get enough to eat. Special sinking foods are a must.

    Some loaches are sensitive to poor nitrogen cycle management, which is why they are included here, rather than in the Good First Fish section. Once the tank is established and the beginner seems to have gotten the hang of maintaining a tank, however, loaches make great additions to most community fish populations.

    The most commonly seen loaches are the Kuhli Loaches – Acanthophthalmus species. These are long, ribbon-like fishes which grow to be 4″ long. Brown with yellow stripes and bands, Kuhli Loaches are shy and spend a lot of time buried in the gravel.

    Another popular group of loaches are the members of the genus Botia. Clown Loaches – B. macracantha, Yo-Yo Loaches – B. lohachata, Skunk Loaches – B. horae, Blue Loaches – B. modesta, and Striated Loaches – B. striata are all seen in the hobby. Some of these (notably Clown and Blue Loaches) can get big, but they grow extremely slowly and can live in a small aquarium for several years. Loaches will often be happier if kept with a few of their own species.

    Weather Loaches – Misgurnus fossilis and Spotted Weather Loaches – Cobitis taenia should be avoided. They are cold water species and have the unfortunate habit of jumping out of aquaria, especially at the approach of a storm.

    Dwarf Plecos

    “Pleco” (a shortening of the now-unused genus name Plecostomus) is the common term used for suckermouth catfish of the family Loricariidae. As mentioned below in the Bad First Fish section, common Plecos (Hypostomus species) are often sold to beginners as algae cleaners. Unfortunately, these fish get too large for the relatively small tanks of most beginners.

    Some species of suckermouth catfish, however, do stay small enough for most beginners to keep. The Clown Plecos of the genus Peckoltia have alternating transverse bands of darker and lighter brown, tan, or yellow and generally stay under 4″ long. The Bristlenose or Bushynose Plecos of the genus Ancistrus possess, as their common names imply, numerous projections from the area between their eyes and mouth. Within each species the bristles are larger on the male, especially near breeding. In fact, Bristlenose Plecos are among the few Loricariids to be successfully spawned in the home aquarium.

    Otocinclus Cats, often just called Otos, are the smallest Loricariids and will clean algae from live plants without hurting any but the most delicate of them. Otos sometimes die shortly after purchase for no apparent reason, but if they make it past this critical time they make very good community tank residents.

    While the various suckermouth catfish will indeed help to keep the aquarium free from many common algae types, the beginner should not make the mistake of thinking of these fish as simply algae eaters or scavengers. They should be given foods intended just for them, such as zucchini which can be blanched or weighted down to sink it to the Pleco’s level. Some fish food manufacturers have recently realized that there is a market for specialized Pleco foods and now sell products such as sinking algae wafers which fit this bill nicely. These foods should be fed in the evening when the light reaching the tank is low, as most Plecos are more active at this time and most other fish which might compete for the food are less active. Pieces of (uncoated) driftwood in the tank are also important for many Pleco species, which rasp at the wood and ingest the scrapings. By the same token, Plecos should *not* be kept in wooden tanks, or even acrylic ones for that matter, as they may chew into the tank material damaging it and/or themselves (by ingesting toxins or undigestible matter).

    Pleco species can be quarrelsome amongst themselves and may be picked on by other fish due to their generally slow-moving nature. Provide a hiding cave for each Pleco and give them territories proportional to their size (e.g. 10 gallons for a 3″ fish.)


    Like many of the fish in the first section, Tetras are schooling fish and should be kept in groups of six or more of the same species. Tetras are native to Central and South America and Africa. In some regions of South America the water is quite soft (very little rock is dissolved in it) and acidic. (Another way of saying “acidic” is to say that it has a low pH – one below 7, which is considered “neutral”. A strong acid has a very low pH. Liquids above pH 7 are said to be “basic”.)

    Unless you know that your tank water is also soft and acidic, the Tetras that need that water should be avoided. Before you buy a Tetra that you are not sure about, look it up in your book. If it says that it needs a pH below 6.5 you should probably avoid it. While many beginning aquarists are tempted to simply adjust the pH of their water by buying little containers of chemicals in the pet store, do not give in to this temptation! Water chemistry is very complex and you can easily kill all your fish by trying it.

    On the other hand, if your tap water is naturally soft and achieves a consistent acidic pH, there is no reason that you can’t try your hand at some of these fish.

    Two very popular Tetras which need soft, acidic water are the Neon Tetra – Paracheirodon innesi and the Cardinal Tetra – Cheirodon axelrodi. These are quite attractive red and blue fish. The red line on the Cardinal runs from the head on back, while in the Neon it starts only in the belly region. But their attractiveness is their only advantage. Besides its water requirements the Neon has the added drawback that almost all of them are bred in the Far East in huge numbers with no regard to quality. Further, the raising ponds for the young fish are filled with medicines. The medicines keep diseases in check but as soon as the fish are shipped they begin to get sick. They die in huge numbers in the stores and in buyer’s home tanks. Probably less than 1 in 10 Neons lives for more than one month after being removed from the pond it was raised in. Further, those two or three tiny neons for a dollar at the local store can easily introduce a disease that kills all the fish in your tank.

    Cardinals will have a greater chance of not dying immediately after purchase but even they will probably not live long in your home tank. They are wild caught in Brazil as adults so they may have lived most of their naturally short life span before you buy them.

    Other Tetras which need acidic water include the Blue Neon Tetra – Hyphessobrycon simulans, the Flag Tetra – H. heterorhabdus, H. metae, the Loreto Tetra – H. loretoensis, the Black Phantom Tetra – Megalamphodus megalopterus, and the Red Phantom Tetra – M. sweglesi.

    So what about those aquarists without acid water? There are plenty of hardy Tetras out there for beginners without special water. These include the distinctive Black or Black Skirt Tetra – Gymnocorymbus ternetzi, the brightly colored Glow Light Tetra – Hemigrammus erythrozonus, the radiant orange Jewel Tetra – Hyphessobrycon callistus, the Flame Tetra – H. flammeus, and the red-tailed Pristella – Pristella maxillaris, all of which grow to less than two inches long. Slightly larger Tetras include the Penguin Tetra – Thayeria obliqua and the closely related Hockey-stick Tetra – Th. boehlkei, both of which are easily recognized by the black lines originating in the lower half of their caudal (tail) fins and running forward, the shiny Diamond Tetra – Moenkhausia pittieri, and the beautiful, trident-tailed Emperor Tetra – N. palmeri. Finally, the only African Tetra frequently seen, the Congo Tetra – Phenacogrammus interruptus is a gorgeous fish which grows up to four inches long.


    Cichlids, members of the family Cichlidae, come from Central and South America and Africa, with a few species found in Madagascar, the Middle East and into Asia. Cichlids are quite unlike any of the fish discussed so far. They are related to and resemble the Perch and Sunfish of US waters. For aquarists, cichlids pose four major problems: (1) Some need special water conditions, (2) some have specialized diets, (3) some get quite large (the largest up to 3′ long), and (4) all are territorial.

    Again, why bother? Because for those willing to take the challenge, the rewards can be great. If any fish can be said to be intelligent, Cichlids can. They display this in their everyday activities as well as in their specialized mating, breeding, and fry-raising activities. The fish mentioned in the previous sections all lay eggs and then ignore or even eat them! Cichlids, on the other hand, care for their eggs and young. It is said that one of the most rewarding sights an aquarist can see is parental Cichlids herding their fry around the tank and protecting them from all dangers. And, even if your Cichlids never breed, they will be more responsive to you than perhaps any other fish. Cichlids can be much more “pet-like” than you might think a fish could be.

    If you do decide to take the Cichlid challenge, choosing your Cichlids can be difficult. Some can be added to your community tank and will do fine with the schooling fish talked about above. These include Curviceps – Aequidens (really Laetacara) curviceps, Dorsigers – Aequidens (again, really Laetacara) dorsiger, and the less frequently seen Nannacara anomala, all from South America, and Thomas’ Dwarf Cichlid – Anomalochromis thomasi from western Africa. Unlike the monster Cichlids, these fish stay small (3 1/2” is a good sized adult) and are relatively peaceful. Two or three may be placed in a 10 gallon tank and they should still all find places to live if there are rocks and other decorations in the tank.

    Other Dwarf Cichlids you may see are the Ram – Papiliochromis (some books use Microgeophagus or Apistogramma) ramirezi, Apistos – Apistogramma species, and the Checkerboard Cichlid – Dicrossus filamentosus (referred to as Crenicara filamentosa in the books). These fish vary in their difficulty for keeping as aquarium fish, but all of them should be avoided by beginners.

    Keyhole Cichlids – Aequidens (really Cleithracara) maronii, Festivums – Cichlasoma (really Mesonauta) festivus, and Angelfish – Pterophyllum scalare can be good fish for the relative novice, but only if healthy specimens can be found and this is often not easy. For this reason, small Keyholes and Festivums should not be purchased. Adults of these two species are generally better choices; still, one should look the fish over carefully and not buy them until they have been in the store tanks for at least a week. Similarly, for the very popular Angelfish, one needs to be very careful when buying them. Before you buy, ask the salesperson to tell you where the store gets its Angels. If the salesperson doesn’t know, won’t tell you, or says that they come from “the wholesaler” (and who knows where before that?) don’t buy them. If you are told that they come from a local breeder then you have at least a chance of getting healthy fish. Also, Angels should be kept in tanks both taller and longer than a 10 gallon aquarium. Keyholes, Festivums, and Angels are all shy fish and should be provided with cover — preferably a planted tank.

    Discus, like Angels, need tanks higher and longer than 10 gallon tanks. Their specialized needs do not stop there, however, and beginners should shy away from these difficult and demanding fish.

    At the other end of the difficultly scale, a very good choice, especially for those with a 20 gallon or larger aquarium, is the “Jurupari” – Satanoperca leucosticta (formerly referred to in the hobby as Geophagus jurupari). It does get large (up to a foot), but it grows very slowly and may still be less than six inches long when several years old. It is a very peaceful Cichlid which will help to clean your tank by sifting through the gravel for uneaten food. A similar fish, Geophagus surinamensis, is also a good choice.

    Kribs or “Kribensis” – Pelvicachromis pulcher are a widely seen West African Cichlid that will do well with the larger schooling fish and should be kept in a twenty gallon or larger tank. Male Kribs grow to be 4″ long and females stay a bit smaller.

    Most of the remaining cichlids which are commonly available are too aggressive and/or grow too large for the beginning aquarist to effectively deal with. This includes the very popular Oscar – Astronotus ocellatus which grows rapidly to over a foot, is opportunistically piscivorous, and is a very messy species. If the aquarist is truly interested in keeping more cichlids than those recommended above, she or he should be prepared to set up special, separate (and probably larger) tanks for these fish and to read more extensively on cichlids before buying them.


    Anabantids are another group of fishes that are quite different from those already discussed. Distantly related to Cichlids and Perch, Anabantids are found in Africa and Asia. Members of the families Anabantidae, Belontiidae, Helostomatidae, and Osphronemidae, Anabantids are also referred to as the “labyrinth fishes”. This is due to a special breathing organ referred to as the labyrinth organ which is essentially a maze of tunnels near the fish’s gills. Labyrinth fish gulp air at the surface of the water and absorb it through the labyrinth organ, allowing them to live in water with too little oxygen to support fish which only breath through their gills. Some Anabantids can survive out of water for several hours breathing only through their labyrinths, as long as they stay moist. Anabas testudineus, known as the Climbing Perch, is said to be able to climb trees and to live out of water for up to two days.

    As well as giving aquarists some additional choices for community-tank fish, Anabantids offer some unique options to fish keepers as well as presenting a few problems. Because some Anabantids are able to withstand cooler temperatures, and because of their ability to survive in water with very low oxygen, these fishes can be kept in tanks or bowls without heaters or filtration. On the other hand, some Anabantids (particularly males of some species) are very territorial and some grow quite large.

    Breeding Anabantids can be quite rewarding. Some species build nests out of bubbles into which they place their eggs while others, like some Cichlids, are mouthbrooders.

    The most commonly seen Anabantid is probably the Betta or Siamese Fighting Fish (which is generally said to be Betta splendens but is probably a crossbreed). Artificial color varieties with red, blue, green, purple, and many other colors in various combinations are widely available. Males are bred to have very large fins and both sexes are seen with double tails. Siamese Fighting Fish generally make poor choices for the community tank for two reasons. First, as their name would imply, they are very territorial. The aggression is greatest between two males, but can be directed towards any fish that looks to the Betta too much like another Betta. Second, their long fins make easy targets for many fish such as Barbs. Siamese Fighting Fish can be kept alone in bowls (the larger the better) or tanks without filtration as long as frequent partial water changes are done. They do need warm temperatures, however, and are sensitive to temperature changes, so a constant heat supply is needed if the room is less than about 75F. Also, due to poor breeding, many Siamese Fighting Fish are not very healthy. A 3″ male would be a large adult; females stay smaller.

    A better choice for keeping alone in a bowl or small tank is the Paradise Fish – Macropodus opercularis. These are much hardier fish than the Fighters and can withstand temperatures down to 60F. They may jump, however, so the tank should be covered to be safe. Also, like Siamese Fighting Fish, male Paradise Fish can be extremely territorial towards one another. Paradise Fish may get up to 4″ long.

    Another very commonly seen Anabantid is the Blue or Three-Spot Gourami – Trichogaster trichopterus. Gold, Silver, and Cosby Gouramies are also widely available and are simply artificial color varieties of the Blue Gourami. Blue Gouramies can get up to 6″ long. They are not as aggressive as Fighters or Paradise Fish, but more than one in a small tank may lead to constant (if not overly deadly) chasing. They will do well in a tank with larger schooling fishes. Similar, though slightly smaller species include the Banded or Giant Gourami – Colisa fasciata (which is only a giant compared to the similarly colored Dwarf Gourami described below), the Thick-lipped Gourami – Colisa labiosa and the somewhat less aggressive Pearl Gourami – Trichogaster leeri and Moonlight Gourami – T. microlepis. The Kissing Gourami – Helostoma temmincki grows larger (up to 12″) but makes a good fish for beginners with larger tanks. It is peaceful, though males will contest with one another by pressing their lips together and pushing – the so-called “kissing” from which the common name derives. Most Kissing Gouramies seen will be of the Pink variety.

    Small Gouramies, only growing to 2″ or so in length, are also available. These include the Dwarf Gourami – Colisa lalia, the Honey Gourami – C. chuna, and the Sunset Dwarf Gourami (probably a cross between C. lalia and C. chuna). In theory, these would all be good fish for the community aquarium. In practice, these fish are often the victims of poor breeding practices in the Far East (like so many others described before) and many are even treated with hormones before they are shipped to make them appear brighter in the store tanks. A good rule of thumb is, “If it looks too good to be true, it probably is.”

    Although harder to find, Anabantids which have had less human interference with their reproduction are generally better choices. Look for the Mouthbrooding Betta – Betta pugnax, the Licorice Gourami – Parosphromenus deissneri, the Spike-Tailed Paradise Fish – Pseudosphromenus cupanus, the Croaking Gourami – Trichopsis vittatus, and the Dwarf Croaking Gourami – T. pumilus, which range in size from 1″ to 4″. Do not buy Chocolate Gouramies – Sphaerichthys osphromenoides which are quite delicate, or the true Giant Gouramies – Osphronemus spp. which grow quickly to well over two feet long.


    The family Poeciliidae contains Guppies, Mollies, Platies, and many other fishes. While these fish are often thought of as beginners’ fish they have been intentionally left off the list until now in order to make a point. The reasons these fish are often sold to beginners are that they are cheap, brightly colored, and have a general reputation among non-aquarists as easy fish. Notably absent from this list is any real suitability for keeping by beginners. For one thing, many livebearers need high level of salt in their water to be healthy – making them incompatible with many other aquarium fish. Many common livebearers also are overbred, resulting in fish not nearly as healthy as those kept by aquarists of previous generations (or by the authors of most books). Some are not even able to reproduce without human intervention. Finally, due to their low market price, they are generally not well cared for and may carry diseases.

    Poeciliids, as they are also called, come from the Americas, primarily Central America. They are called “livebearers” (as opposed to “egg-layers”, as all the previously discussed fish have been) because the eggs are fertilized within the female and the fry do not appear until the eggs have hatched. There are also livebearers from other families in which the details of reproduction vary.

    The well-known Guppy can be found in a number of colors and with as many as 12 different artificial tail varieties. Also available is the closest thing that you may find to the wild Guppy – Poecilia reticulata: “feeder Guppies” which are not bred for color. The fancy strains tend to be fragile while common Guppies often carry diseases. Guppies should be kept in water with at least one teaspoon of salt per five gallons of water.

    Common Mollies are the Black Molly (which was derived from the Marled Molly – Poecilia sphenops) and the Sail-Fin Molly – Poecilia velifera (of which there are also several color varieties available). Black Mollies need at least one teaspoon of salt per five gallons of water to keep them healthy and prevent the outbreak of “ich” (Ichthyophthirius multifiliis, a parasite commonly seen in aquaria) while Sail-Fin Mollies need at least three times this amount. Sail-Fins grow to 6″ while Black Mollies stay less than 3″.

    Closely related, Swordtails – Xiphophorus helleri and Platies – Xiphophorus maculatus are also popular fish. A number of color and finnage varieties are available of each with some of the Platies also referred to as “Moons”. These fish need at least a teaspoon of salt per 5 gallons of water to be healthy. Some varieties are susceptible to various maladies (Tuxedo Swords often get tumors, for instance) and as with so many other fish the naturally colored fish are probably your best bets. “Green Swords” (which are really multi-colored) are naturally colored X. helleri, but unfortunately wild morphs of Platies are not often seen. The Variegated Platy – Xiphophorus variatus is sometimes seen, however, and fills this role nicely.

    Bad First Fish

    We have already discussed several poor choice for beginners’ fish alongside their more desirable cousins. Here are more fishes that are seen in the stores that beginners should be warned about. Many of these fish make good fish for advanced hobbyists while others never make good aquarium fish. Some are even suitable for a well-informed beginner; you just need to know what you are getting yourself into before you buy the fishes on impulse and drop them into your community tank.


    Goldfish are one of the most common fish sold to beginners, but are particularly poorly suited to this role. The common Goldfish sold as feeders are generally full of diseases and parasites which may kill them and other fish they are housed with. Fancy varieties, which have been selectively bred for centuries to achieve their unnatural appearances, are subject to a host of problems associated with their abnormalities.

    All Goldfish are cold water fish which do not do well in the lower oxygen levels found in tropical aquaria, and therefore should not be housed with tropical species.


    Piranhas are among the most abused of all aquarium fish. They are often purchased in order to watch their legendary feeding habits. As mentioned above, feeder fish often bring diseases and parasites with them and these can infect Piranhas. A regular diet of feeder fish can also be quite expensive.

    Piranhas are schooling fish and are generally shy and stressed when kept as single specimens. Unfortunately, they also get big (many species well over a foot long), so most beginning aquarists don’t have room to house more than a single Piranha. If enough tank space is available to keep several Piranhas together, they must be kept well fed or they will turn on each other, killing and cannibalizing one fish after another.

    Knife Fishes

    There are several families of fish from South America, Africa, and Asia, referred to as Knife Fishes. Many species of Knives get large, some over 3′ long although some of the less attractive species stay as small as 8″. All of them are nocturnal predators, a fact that many a beginner could have used before all of his or her small fish “mysteriously” disappeared a few at a time.

    Hatchet and Pencil Fishes

    Somewhat related to Tetras, Hatchets (family Gasteropelecidae) and Pencils (genus Nannostomus) are Characins from South America. Many of them need soft and acid water and all of them are delicate. Hatchets have the added disadvantage that they tend to launch themselves out of the aquarium to an untimely death.

    Elephant Nose and Baby Whale

    More fragile fish include Elephant Noses – Gnathonemus petersi and Baby Whales – Petrocephalus bovei. African fishes from the family Mormyridae, these are night feeders and are hard to provide for in the aquarium.

    Chinese Algae Eater

    Chinese Algae Eaters – Gyrinocheilus aymonieri are often introduced into the aquarium to do what their common (sales) name implies – eat algae. They are usually seen at a small size and many die within a short time of purchase. If they live, however, they get big (up to a foot long) and tend to prefer to rasp at the sides of slow moving fish (making them susceptible to infections) to eating algae.

    Bala Shark

    Not a shark at all but a Cyprinid (related to the Carp), Bala Sharks – Balantiocheilus melanopterus quickly outgrow most home aquaria. They get to be over one foot long.

    Iridescent Shark

    Unrelated to the Bala Shark or to true sharks, the Iridescent Shark – Pangasius sutchi is a catfish. It grows to over 3′ and tends to injure its nose against the aquarium glass.

    Glass Catfish

    Another catfish to avoid is the Glass Catfish – Kryptopterus bicirrhis. While it stays small enough to be an aquarium fish (up to 6″), it is very delicate and should not be purchased by beginners.


    The suckermouth catfish of the genus Hypostomus are often sold in the stores as algae cleaners. Most of these species get in excess of 12″. Some of the slender suckermouth catfish, such as the Whiptail – Dasyloricaria filamentosa and the Farlowella – Farlowella gracilis, are quite delicate species.

    Long-Whiskered Catfish

    Catfish don’t have long whiskers for looks. They are there to help them hunt for their food – other fish! In addition to eating all fish of less than half their size in the tank, many of the piscivorous (fish-eating) Cats will outgrow most tanks. One common species of long-whiskered catfish, the Pictus Cat – Pimelodus pictus grows to 10″ while the Channel Cat (a pink form is often seen) grows over 2 feet long. Shovelnose Cats are usually only seen at six inches or greater, so the beginner does have some warning with these. Still, one might not expect them to get 2 or 3′ long.

    Red-Tailed Catfish

    Red-Tailed Catfish – Phractocephalus hemiliopterus are particularly large-growing predatory catfish. A dark body with a horizontal white stripe and red tail gives them an attractive appearance at a small size that has unfortunately made them a popular aquarium fish with those who fail to appreciate the enormity of adults. Adults may grow to well over 4′ in length and have mouths that more than match their lengths. As such, they are more than many public aquaria can house, not to mention private aquarists.

    Spiny Eels

    Spiny Eels (family Mastacembelidae) are aggressive fish, some of which grow quite large (over 3′). Some do stay small (less than 4″ for one species), but all are likely to have internal parasites.

    Painted Glassfish

    Painted Glassfish are Glassfish – Chanda ranga which have been “painted” with chemical dyes. This procedure adds a temporary bit of unnatural color (which disappears with time) and stresses the fish, causing them to be prone to diseases and parasites. This fish needs at least 1 teaspoon of salt per gallon of aquarium water.

    Dyed Fish

    While Painted Glassfish were for a long time the only fish commonly seen that had been “colorized” by unscrupulous marketers, the last few years have seen several other fishes subjected to this abuse. One of these is the White Skirt Tetra (an albino version of the Black Skirt Tetra – Gymnocorymbus ternetzi) which are sold as Blueberry Tetras, Strawberry Tetras, Rainbow Tetras, etc. depending on the dyes used to color the individuals. Similarly, Blueberry and Strawberry Loaches have also been seen. If you are unsure if a fish has been dyed, ask.

    Brackish Water Fish

    I have already mentioned some fish, such as Mollies and Glassfish, which come from brackish waters – I simply have not called it that before. Brackish water is intermediate between the fresh water of most rivers and lakes and the salt water of the Oceans. Brackish water is found in gulfs, deltas, and lagoons, as well as a some lakes and rivers. Because brackish water fish need so much salt in their water they are not compatible with most aquarium fish. Further, brackish water fish generally need more room per fish to stay healthy than freshwater fish. Some commonly seen brackish water fish include Monos – Monodactylus species, Archers – Toxotes species, Scats – Scatophagus species, and many species of Puffers (family Tetraodontidae).

    Salt Water Fish

    If brackish water fish are to be avoided by beginners, then beginners should stay well away from salt water fish. Their bright colors are attractive, but they are generally much more difficult for beginners to keep alive than are fresh water fish.


    There are thousands of species of aquarium-suitable fish from a host of families that are not covered above; this article is far from comprehensive. Killifish (fish of the family Cyprinodontidae) for example, are widely kept by many advanced hobbyists, but not often by beginners. This is not because they are all unsuitable as beginner’s fish. In fact, some of them would make very good first or second fish. They are simply not widely available in pet stores.

    For choices of good beginners’ fish beyond those listed here, and for expanding once one has moved beyond the beginner level, local aquarium clubs and friends who are aquarists can be very good sources of information. So can many of the available fishkeeping books and magazines. At every level of experience, the aquarist will find that good information is well worth the time and/or money it takes to get it.

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