Stocking a Peaceful Community Tank

Stocking a Peaceful Freshwater Community Tank
The choices below are arranged by tank size, obviously those listed for the smaller tank would be suitable for the larger tanks and appreciate more space, but not vice versa! All tanks should have completed the nitrogen cycle beforehand and all fish listed are tropical fish so require a heated tank.

The fish listed are considered entirely peaceful. They will not eat or bully tank mates. Some may show a tendency to fin nip however if kept in too small a group or kept with slower fish. It must also be born in mind that larger fish, no matter how peaceful, may still consider much smaller fish as a meal, even if they're known for being vegetarian! Always research fish species extensively before purchase.

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See Stocking a 10 Gallon Tank and Stocking a 5 Gallon Tank.

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Neons are peaceful and common shoaling fish. In order to have a healthy group they should be kept in a minimum of 6-8 individuals. Smaller groups will be shy and withdrawn and may turn to nipping at tank mates. In a a maximum of 8-10 should be considered. They are mid to top dwelling fish and kept with other peaceful fish will not shoal tightly together and will spread throughout the tank.
 * Neon Tetra (Paracheirodon innesi)

The Glowlight has exactly the same needs as the Neon Tetra, in fact it looks very similar but is minus the bold blue markings and has a red lateral stripe rather than blue. In this size tank a group of 6-10 would be suitable and, like the Neon, will not shoal tightly when it's secure in its own environment.
 * Glowlight Tetra (Hemigrammus erythrozonus)

The Green Neon Tetra is the opposite of the Glowlight Tetra. It lacks the red horizontal band but has a strong lateral green/blue iridescent band from the nose to the caudal peduncle. Like the Glolights and Neons, they're happiest in groups and otherwise have very similar care needs.
 * Green Neon Tetra (Paracheirodon simulans)

The Cardinal Tetra is like an over-sized Neon Tetra, instead of having the red colouring on only half the body, on the Cardinal it extends from the gill plates to the caudal fin. They are larger than Neons but have the same care needs, to be in a shoal of 6 or more in a laterally spacious tank.
 * Cardinal Tetra (Paracheirodon axelrodi)

Otos (usually Otocinclus macrospilus, Otocinclus mariae or Otocinclus vittatus) are some of the smallest of the Pleco family available in the pet trade. These tiny suckermouth catfish are sociable, and best kept in groups of 3 or more. They are excellent little algae eaters, but will only eat some soft algaes, they will not touch hair algae or tough green spot algae. They benefit from bogwood being present and will need supplementary feeding of sinking algae wafers and blanched vegetables. These little fish are almost always wild caught and can be very delicate, they should only be added to mature tanks at least 6 months old. They often have a fairly poor survival rate in captivity.
 * Otocinclus (Otocinclus sp)

This is a small and entirely peaceful Pleco that may get mislabelled as Otocinclus. Like Otos, they're happiest in groups and will eat some soft algaes, and also be supplemented with algae wafers and blanched vegetables. Should happily cohabit with other peaceful similar sized fish without any problems. They are at risk of being eaten by larger fish though.
 * Pitbull Pleco (Parotocinclus jumbo)

With similar shoaling habits to the Neon Tetra, the Harlequin is a popular alternative to Tetras. It is entirely peaceful and best in groups of 6 or more. It is mid-top dwelling and its orange colouration is quite striking against a green planted backdrop.
 * Harlequin Rasbora (Trigonostigma heteromorpha)

A very common and well loved fish. The fancy males, with their long colourful fins, are a popular choice. These are very prolific livebearers and females should be kept with caution, even without males present they can still give birth if they were kept with males at the breeders or at the store. For a worry-free tank, keep males only. In a group of 4-5 plus they should not worry each other. They are active fish and appreciate lateral swimming room, however, the long-tails of fancies mean they cannot be kept in tanks with strong currents.
 * Guppy (Poecilia reticulata)

An interesting alternative to more well known shoaling fish. The Threadfin is very distinctive to look at and entirely peaceful. It's best to keep 1 male to 2-3 females, more than one male to a tank is advisable as this is when they show their best colours as they show off towards each other. They shouldn't fight. Due to their long fins it's best they're not kept with anything that may even slightly nip such as Tetras.
 * Threadfin Rainbowfish (Iriatherina werneri)

The Cherry Barb is one of the more peaceful of the Barb family. Unlike it's notoriously nippy cousin, the Tiger Barb, the Cherry will generally be fairly oblivious to tank mates as long as they're kept in a good group, several females to a male are recommended, a minimum of 6 individuals makes for a good group. They shouldn't be nippy, but do not keep with very long finned fish just in case!
 * Cherry Barb (Puntius titteya)

This Hatchetfish is entirely top-dwelling, the same as its other Hatchetfish cousins. It is entirely peaceful and must be kept in groups of 6 or more, smaller groups will leave the fish stressed and far more likely to jump. Speaking of jumping, these guys are pros and a tank with Hatchets must have a very secure lid with no holes at all, and be wary when you have the lid open for routine maintenance too! They work well with mid-bottom dwelling fish and should really be kept as the only top-dweller.
 * Marbled Hatchetfish (Carnegiella strigata strigata)

The Dwarf Pencilfish is small and peaceful and an interesting alternative to Tetras. It's not strictly shoaling but does better with others of it's own kind, keep in groups of at least 3-4 or more. They are tiny and shouldn't be kept with much larger or boisterous fish.
 * Dwarf Pencilfish (Nannostomus marginatus)

A well known Gourami that must be bought with caution. They are known to carry their own virus, the Dwarf Gourami Iridovirus, any tanks with sick fish should be avoided, and any fish shipped from Asia should definitely be avoided. Apart from that, a male alone, or a male/female pair would be fine in a. Do not keep two males as they will fight. They are otherwise peaceful fish who occupy the mid-top levels of the tank.
 * Dwarf Gourami (Colisa lalia)

The Honey Gourami is a colourful addition to a small community tank. They are generally peaceful, but two males can be aggressive to one another. It's best to keep either a single male, a single female or a male/female pair, in you could keep one male and several females. Due to their long ventral fins, they should not be kept with nippy fish and should not be mixed with other Gourami species.
 * Honey Gourami (Colisa chuna)

Also commonly seen in albino, this is one of the most well known Corydoras. They get to around $$ and in a only 3-4 should be kept. They must be kept with others of their own kind however as they love company of their own and will bumble around the bottom of the tank scavenging for food and will not bother tank mates.
 * Bronze Corydora (Corydoras aeneus)

An attractive spotty Corydora also often seen and a good alternative to the Bronze Corydora. It stays a little smaller than the Bronze at $$ and also must have company of it's own kind, again 3-4 in a, more in larger tanks.
 * Sterbai Cory (Corydoras sterbai)

Another common and popular livebearer, the Platy is a good colour choice for an aquarium. Selectively bred with many colours now available including orange and blue. Like other livebearers, they are very prolific, to stop overstocking with unwanted fry, keep males only. They should not bother other tank mates.
 * Platy (Xiphophorus maculatus)

An attractive alternative to other small groups of fish. Should be kept in groups of their own kind, 5-6 in a. Males should be kept in similar ratios as with livebearers as males will show some aggression towards one another. Avoid keeping with long-finned fish but should be fine with other fish like Tetras.
 * Forktail Rainbowfish (Pseudomugil furcatus)

Stocking Suggestions
In this size tank it's recommended to consider one group of shoaling fish, with a small group of bottom dwellers and one (or a pair) of centrepiece fish. For example: Or a variation on that. For a first community tank this would be ideal. Once you become more experienced variations on this can be considered.
 * 6 Neon Tetras
 * Male/Female Dwarf Gouramis
 * 3-4 Bronze Corydoras

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Zebra Danios (and their cousins the Leopard Danio) are often marketed for much smaller tanks, these very active fish really need as much lateral swimming space as possible. They should be kept in groups of 6 or more, smaller groups may result in them turning to fin nipping and bothering tank mates. They are mid-top dwelling and shouldn't be kept with slower moving mid-top dwellers like Gouramis as their active nature could be bothersome. Zebras are ideal for a highly-active community. An active mid-swimming peaceful shoaling fish. Keep this Rainbowfish in groups, more females than males. They should not bother tank mates, but do not keep with very long-finned fish. They are otherwise entirely peaceful and a good alternative to Tetras and Rasboras. Do well in planted tanks. A larger Tetra that must be in groups of 5-6 or more. Will mostly occupy the mid-bottom levels of the tank and can be sensitive to water quality, so regular water changes and mature tanks are a must. An otherwise peaceful active fish provided it's kept in a good shoal.
 * Zebra Danio (Brachydanio rerio)
 * Dwarf Neon Rainbowfish (Melanotaenia praecox)
 * Rummynose Tetra (Hemigrammus rhodostomus)

An unusual and popular eel-like fish, the Kuhli Loach is entirely bottom dwelling and requires a soft sand or small soft gravel substrate in which to burrow. They must be in groups of 4-5 or more, otherwise they'll be so shy they'll never be seen. They are oblivious to tank mates and due to their slender size to not offer much in the way of mess in terms of bioload. Can uproot live plants.
 * Kuhli Loach (Pangio kuhlii)

Stocking Suggestions
This size tank should be stocked carefully also, and always bear dimensions in mind! You can still go with the basic one shoal/some bottom dwellers/centrepiece option though, just a couple more shoalers would work, a stocking example could be:
 * 6 Rummynose Tetras
 * 5 Kuhli Loachs
 * 1 Male Dwarf Gourami
 * 2 Female Dwarf Gouramis

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This is one of the smaller and most well known Synodontis. It is an active mid-bottom dweller that will characteristically swim entirely upside down. They are sociable fish and must be kept in groups of 4-5 or more, in smaller groups they may be nippy and one will become dominant. They should not be kept with smaller fish but will be peaceful towards other larger peaceful community fish. They are active swimmers that require plenty of space as well as hiding places. The Brochis Catfish looks like a giant Bronze Cory. They get to around $$ (sometimes a little larger), and like the Bronze Cory are happiest in schools of their own kind. They will not bother any tank mates and keep to themselves. Due to their larger size, they do better in larger tanks than the Bronze Cory.
 * Upside-Down Catfish (Synodontis nigriventris)
 * Emerald Catfish (Brochis splendens)

An attractive and popular larger Tetra, the Congo does well in a group of at least 5 or more. They are very pretty fish with long flowing tails which rules them out from being kept with anything that may fin nip. They are mid-top dwelling active fish that do well in a long tank with a good mix of open swimming space and hiding places in tall plants.
 * Congo Tetra (Phenacogrammus interruptus)

An interesting fish with an entirely transparent body. This catfish gets approximately $$ in length so requires a spacious tank. They can be pretty shy so must be in groups of at least 4-5 or more. They should cohabit peacefully with similar sized peaceful fish, but will be bullied by more boisterous fish. Does not cope in strong currents or very bright lighting, does best in densely planted mature tanks.
 * Glass Catfish (Kryptopterus bicirrhis)

A peaceful and shy fish with very similar needs to the Glass Catfish above. This fish must be kept in groups of at least 5-6, they do not do well alone at all, and must have some shelter such as dense planting and caves in which to dart into if startled. They also won't be happy with very bright lighting. They get to around $$ and are quite distinctive little fish, generally keeping to the mid-bottom levels of the tank but not sitting on the substrate.
 * African Glass Catfish (Pareutropius buffei)

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These are popular large bottom-dwelling fish. They are very large growing, at around $$ and a final tank size of over should be considered. Despite their large size, they grow slowly, it will take several years for them to reach their full potential, so can be kept in smaller housing of around, but this should only be temporary. Like most common Loaches, they are very sociable and must be kept in groups of at least 3-4 or more. They are bottom dwelling and ideally should be the only bottom-dwellers. They may eat small fry but are otherwise oblivious to tank mates as long as they have company of their own kind.
 * Clown Loach (Chromobotia macracanthus)

A very colourful larger Rainbowfish. These are sociable fish and are best in groups, with more females per males, but keeping several males will result in the best colour displays. They shouldn't be kept with much smaller fish nor with very long-finned fish. They are active mid-swimming fish that do well in planted tanks with open swimming space.
 * Boesemani Rainbowfish (Melanotaenia boesemani)

Another large growing Rainbowfish. The Red Rainbowfish is exactly that, it is a vibrant bright red all over and adults are surprisingly chunky fish too. They are sociable and like other Rainbows are best kept in groups with more females than males, the males will display to one another. They are peaceful but are very active fish, so do not keep with shy slow swimming fish as they may get scared into the shadows with these fish buzzing around the tank. Their bright colour looks fantastic against a green planted backdrop.
 * Red Rainbowfish (Glossolepis incisus)

The Common Pleco is technically a common name for 3 very similar looking species, only an experienced eye can differentiate them. This fish is often sold as a "cleaner" for smaller tanks, trouble is it grows over $$ and is therefore only suitable for very well filtered larger tanks. They are generally oblivious to tank mates and will busy themselves grazing on bogwood. They are, however, territorial towards other Plecos so only one Pleco to a tank! They should be supplemented with blanched vegetables and sinking algae wafers, they may also nibble on other meaty foods like bloodworm that's been put in for tank mates. Do not keep with very small fish or fish that may fin nip. They are primarily nocturnal so need plenty of gloomy hiding places and will be most active and be more likely to feed at night. Planted tanks don't do well with Plecos, they will uproot delicate plants.
 * Common Pleco (Hypostomus plecostomus)/(Pterygoplichthys pardalis)/(Hypostomus punctatus)