I can vividly recall my visit to the local pet store after acquiring my first aquarium more than 40 years ago. I had no idea what fish would do well in my modest 10-gallon aquarium. When you search the tanks of fish stores, no doubt you have seen that some of them provide labels with basic information, such as the fish’s name, maximum size and compatibility. Although these labels are a good starting point, your next source for information would be the sales staff. In addition, I suggest joining a club, talking to other aquarists and accessing other resources, such as the Internet, books and magazines.
The goal of this article is to discuss commonly available fish that are good candidates for a community aquarium. Please keep in mind that nothing written here is carved in stone. Although some fish may generally be peaceful, not every individual of each species may behave the same. Most importantly, the environment that we provide for our fish can play a major role in their behavior. For example, the size of the aquarium and how it is aquascaped will affect the amount of space available, which can have a direct effect on stress levels, establishment of territories, territory size, health, etc. In addition, behavior may be altered based on the number of fish, age, sex ratio and size of other fish in the aquarium.
Of all the ornamental fish available to the fish hobbyist, labyrinthfish would certainly be considered some of the most interesting and colorful. These fish obtained the collective title of labyrinthfish owing to the supplementary respiratory apparatus they all share in common.
Outside of their striking colors that make them attractive to the hobbyist, various labyrinthfish have some unique behaviors, including oral incubation, sound production and the ability to migrate across land in pursuit of other bodies of water. If their striking colors and unique behaviors are not enough to pique your interest, most labyrinthfish are hardy, and few have special requirements.
A number of small- to moderate-sized gouramis are well-suited for a community aquarium, including the honey gourami (Trichogaster chuna, 1.5 inches), dwarf gourami (T. lalius, 2 inches), sunset gourami (T. lalius var., 2 inches), croaking gourami (Trichopsis vittata, 1.5 inches), pygmy gourami (T. pumila, 2.25 inches) and pearl gourami (Trichogaster leeri, 4 inches). In general, these species will do well in slightly acidic to neutral water (pH 6.5 to 7.0), a water temperature of about 77 degrees Fahrenheit, and a water hardness between 5 and 7 dH. Ideally, the aquarium should be aquascaped with driftwood, densely planted with groups of live plants and well-lit. As omnivores, these fish will readily accept a variety of dry and live foods. To read more about the gourami fish, click here.
The vast majority of the livebearers common in the aquarium trade belong to the family Poeciliidae, such as the guppy, swordtail, and platy. There is also the molly, which is a bit more difficult to care for due to its salt requirements. Except for the fact that some livebearers will eat their young or the young of others, you’d be hard-pressed to go wrong with livebearers in a community tank. These fish are hardy, inexpensive and easy to breed. Cross-breeding has produced a plethora of different and interesting colors, patterns, finnage and shapes – and this variety can excite even the most seasoned hobbyist. Read more about livebearers here.
The guppy (Poecilia reticulata) is one of the best known of all ornamental fish, with hundreds of varieties that differ in color, body pattern and fin type. The different color patterns are displayed more predominantly in males, which are smaller than females. Guppies really look impressive in a small- to moderately sized school in a single-species aquarium; however, guppies can easily be kept in a community aquarium with other moderately sized, non-aggressive fish. The average size of a guppy is about 2 inches. They accept a variety of commercially prepared and live foods, prefer slightly alkaline water (pH 7.5) and need a water temperature ranging from 72 to 77 degrees Fahrenheit. Read more about guppies here.
Although the wild-type swordtail (Xiphophorus hellerii) displays hues of green, blue and red, which can vary considerably geographically, it is still rather plain compared to aquarium strains. Some of the more interesting and colorful swordtails include the black calico, golden comet, lyre-tailed, pineapple, black, red wag, etc. Although females are slightly larger, more robust and just as colorful as males, the males are striking, owing to their swordlike extension of the lower caudal fin rays. Read more about swordtails here.
Because swordtails attain a maximum size of approximately 4 inches, keep them in at least a 10-gallon aquarium. Swordtails prefer slightly hard (10 to 15 dH), alkaline water (pH of about 7.5) at a temperature ranging between 70 and 77 degrees. To optimize their health (especially if you hope to breed them), feed them a variety of commercially prepared foods and small live foods (e.g., brine shrimp, bloodworms). In addition, they may pick at some algae, but don’t expect them to provide much assistance in controlling algal blooms.
In the confines of an aquarium, male swordtails will often establish territories where they will constantly strut their stuff around females. Maintain swordtails at a ratio of one male for every three females. Swordtails should not be housed with platies, as they will readily interbreed. Lastly, swordtails (especially males) are great jumpers, so make sure the top of the aquarium is well-covered.
Platies available to hobbyists actually represent two different species: Xiphophorus maculatus and X. variatus. Attaining a maximum length of 3 inches, X. maculatus is slightly smaller than the swordtail, and has a broader body and rounder finnage. The overall color of wild platies is an olive-brown hue, though some specimens exhibit a distinct red color; this red color is clearly apparent in domestic strains. Numerous strains (e.g., Mickey Mouse, blue, blue one-spot, red wagtail, pintail red wagtail, gold comet, coffee and ink, blue coral, black, marigold hi-fin, orange, green, tuxedo) have been produced through selective breeding and hybridization with other Xiphophorus species, especially the variegated platy (X. variatus). The variegated platy attains a maximum size of approximately 3 inches. Breeders have produced a plethora of different variegated platy strains (e.g., sunset, blue tuxedo, calico, green, hi-fin golden parrot, golden) to such an extent that wild-type strains are difficult to find. Both platy species will readily hybridize with one another and with swordtails.
Both platy species are social and peaceful, so they do nicely in a community aquarium. An aquarium of at least 10 gallons containing slightly hard (10 to 15 dH) and slightly alkaline (pH of about 7.5) water between 68 and 77 degrees is preferred. To optimize their health, especially if you hope to breed them, feed these fish a variety of commercially prepared foods (e.g., flake, frozen, freeze-dried) and small live foods, such as brine shrimp. The platy diet should have a high degree of vegetable matter. Platies tend to be less aggressive than swordtails, therefore a sex ratio of one male to two or three females will suffice.
Most cyprinids kept by aquarists have a strong schooling instinct and are best maintained in small- to moderate-sized schools. White clouds. The white cloud (Tanichthys albonubes) is often the first egglaying fish bred by aquarists. They are easy to care for, not prone to any particular disease and are prolific. White clouds are relatively small (approximately 1.5 to 2 inches) and have a slender, classic fish shape. The basic body color pattern consists of a gold-brown hue with a horizontal gold stripe running the length of either side of the body. There is red at the base of the dorsal and anal fins, caudal peduncle and near the operculums. Although a variety of different variants have been selectively bred (e.g., yellow, red, blue, black and brown), they all share the bright stripe running the length of the lateral line on either side of the body. Males tend to be more slender and more brightly colored than females.
Due to their small size and peaceful demeanor, white clouds are popular schooling fish for a community aquarium. That said, white clouds should be housed with other docile fish similar in size, such as tetras, platies, swordtails, guppies, rasboras, zebra danios, Corydoras species, etc. Since white clouds are active schoolers, it is suggested that a school of at least six individuals be housed in an aquarium of at least 10 gallons, though a larger aquarium is suggested. It is best to keep more females than males, as this reduces the amount of competition for mates.
The aquarium should be aquascaped with plants and have plenty of light, but it is important to provide enough open space (hence the larger aquarium). Although white clouds are not notorious jumpers, it is still advisable to use a full hood or glass cover. Water parameters include a temperature between 73 and 78 degrees, a pH of about 7.0, slightly soft to hard water and excellent water quality.
When it comes to diet, white clouds are not fussy eaters, as they will readily accept any commercially prepared flake, frozen or freeze-dried foods, as well as live foods, such as brine shrimp, bloodworms and blackworms. As always, a varied diet is the best approach in maintaining excellent health.
The zebra danio (Danio rerio) is a relatively small (2 to 2.5 inches), slender fish. The body pattern consists of horizontal blue-gray stripes against a gold background (more yellow in females). In some individuals, the blue stripes may be broken into spots or short segments. Over the years, numerous variants have been selectively bred, including the golden, long-fin, metallic long-fin, albino, veil-tailed, sunset orange and red.
Due to their small size and peaceful demeanor, zebra danios are popular schooling fish for the community aquarium. Because this is an active schooling species, it is suggested that a school of at least six individuals be housed in a 20-gallon or larger aquarium. The aquarium should be aquascaped with plants and have plenty of light, but it is important that they have plenty of open space. A small school can be kept in an aquarium as small as 10 gallons, but this aquarium offers limited open space. In addition, if not kept in a school, some individuals may exhibit more aggression. If you plan on keeping any of the long-fin variants, do not keep them with fin-nipping tankmates (e.g., barbs, Buenos Aires tetras, etc.). Zebra danios are notorious jumpers, therefore make sure the aquarium is covered. They can jump through the smallest of holes associated with filters, electrical cords, etc., so block all holes.
Native to the waters of India, from Calcutta to Masulipatam, zebra danios are accustomed to slightly cooler water (68 to 75 degrees) but will acclimate to the higher temperatures required by the majority of tropical fish. In addition, they prefer slightly hard (5 to 12 dH), slightly acidic to neutral water (pH 6.5 to 7.5). As omnivores, they will accept a variety of commercially prepared foods and live foods (e.g., blood-, white- and blackworms, brine shrimp, vestigial adult Drosophila, mosquito larvae). Zebra danios are easy to breed and are prolific; they lay as many as 200 to 500 eggs per spawning event. They are unique in that they are loyal and devoted to their mates, and they rarely spawn with others. Read more about the zebra danio here.
Two algae-eating cyprinids fit well into community aquariums: the flying fox (Epalzeorhynchos kalopterus) and the Siamese flying fox (Crossocheilus oblongus). Both species remove algae attached to the leaves of live plants without harming them, and they will eat the dreaded thread algae. Both species grow to a size of approximately 5.5 inches. They prefer clear, well-oxygenated, moderately hard (15 dH), slightly acidic (pH from 6.5 to 7.5) water at a temperature ranging between 72 to 79 degrees. Both species can easily be kept in small schools of four to six individuals. Read more about algae eating fish here.
Fortunately, the beginner aquarist has many barbs, rasboras and loaches to choose from. Barbs of interest might include the long-finned rosy barb (Puntius conchonius var.), cherry (P. titteya), striped (P. fasciatus), checkered (P. oligolepis) and golden barb (P. sachsi). Many rasboras, such as the harlequin rasbora (Trigonostigma heteromorpha), red-tailed (Rasbora borapetensis), pearly (R. vaterifloris) and scissor-tailed rasbora (R. trilineata), are good alternatives. The dwarf or pygmy rasbora (Boraras maculatus) is another possible alternative, but because of its small size (0.75 inch), other fish in the community must be of similar size.
A vast array of tetras are well-suited for the community aquarium, including the blue emperor tetra (Inpaichthys kerri), cardinal (Paracheirodon axelrodi), neon (P. innesi), black-lined (Hyphessobrycon scholzei), rosy (H. rosaceus), rummynose (Hemigrammus rhodostomus), glowlight (H. erythrozonus), serpae (Hyphessobrycon eques), red phantom (Megalamphodus sweglesi), blind cave (Astyanax fasciatus mexicanus) and diamond tetra (Moenkhausia pittieri). These tetras are peaceful, vary in size from 1.5 to 3 inches and show themselves off well if kept in schools. Provide these tetras with soft (1 to 2 dH), slightly acidic water (pH 6.0 to 6.5) at a water temperature of 72 to 79 degrees. Tetras are not fussy eaters, and they will eat a variety of commercially prepared and small live foods. Other characoids that the hobbyist might consider include the different species of Nannostomus pencilfish, which should be maintained in small schools. Check out the variety of tetra species here.
The morphology and requirements of cichlids is as diverse as their origin. This said, a lot of cichlids are not suited for a community aquarium due to their size, behavior and special needs. However, some of the acaras and dwarf cichlids will do nicely in a community aquarium. Acaras are mild-tempered, and many acara species will coexist in a large community aquarium with similarly sized fish. Good candidates include the keyhole cichlid (Cleithracara maronii, 6 inches) and the blue acara (Aequidens pulcher, 8 inches). Both species will eat a variety of commercially prepared and live foods. They prefer slightly acidic (pH 6.5) to neutral, soft (about 5 dH) water and a temperature between 70 and 77 degrees. Alternative acaras include the flag acara (Laetacara curviceps), Paraguay acara (Bujurquina vittata) and orange-fin acara (Laetacara thayeri).
Dwarf cichlids (e.g., Crenicara spp., Apistogramma spp., Mikrogeophagus spp.) are well-suited to a community aquarium due to their small size (3 to 4 inches) and docile behavior. The fact that they won’t uproot plants is an added bonus. General water requirements and diet are similar to the acaras.
More information about cichlids can be found here.
As always, before making any purchase, do your homework. Although it may be tempting to make an impulsive purchase, it may lead to stress, disease and the death of your other prized fish. Don’t rely on the pet store staff for all the answers. Assume the brunt of the responsibility in determining compatibility among different fish. Nothing is more disheartening than to observe one incompatible fish completely destroy the harmonious community that you’ve worked so hard to maintain. AFI
Jeffrey C. Howe has maintained aquariums for 40 years and has been writing for fish hobbyist publications for the past 20 years. He is currently employed by the U.S. Fish and Wildlife Service as a marine biologist.