5 Gallon
A popular desktop aquarium size. The 5-gallon is widely considered the absolute minimum required volume for a single Betta fish.
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A popular desktop aquarium size. The 5-gallon is widely considered the absolute minimum required volume for a single Betta fish. With a capacity of 19 litres (5 gallons) and dimensions of 41 x 20 x 25, this standard tank is compatible with 18 species in our database — giving you plenty of options for a thriving community setup.
Stocking Tips
- 💡Avoid overstocking — smaller tanks are less forgiving of water quality swings. Frequent water changes are essential.
- 💡Stick to nano-friendly species. Even a few extra centimetres of fish can overwhelm a tank this size.
Stocking Recipes
Pre-built species combinations that work well together in this tank.
Nano-Friendly Mix
- Chili Rasbora×6Schooling
- Bladder Snail (Pest Snail)×1Bottom Dweller
Low Maintenance Setup
- Chili Rasbora×6Schooling
- Thai Micro Crab×3Bottom Dweller
Schooling Showcase
- Chili Rasbora×6Schooling
- Bee Shrimp (Crystal Red / Black)×10Bottom Dweller
Colorful Community
- Clown Killifish×4Schooling
- Assassin Snail×1Bottom Dweller
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Commonly Mis-Stocked
These fish are frequently added to this tank but may outgrow it or cause problems. Proceed with caution.
Bladder Snail (Pest Snail) fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Cherry Shrimp fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Endler's Livebearer fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Ghost Shrimp fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Least Killifish (Heterandria) fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Malaysian Trumpet Snail (MTS) fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Mystery Snail fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Rachov's Killifish (Annual) fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Ramshorn Snail fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Centerpiece Fish
Bold, eye-catching species that serve as the focal point of your tank. Typically kept singly or in pairs.
Betta (Siamese Fighting Fish)
Betta splendens
The Siamese Fighting Fish is an aquarium icon known for its labyrinth organ (allowing air breathing) and vivid colors. While hardy, they require heated, filtered water (24-30°C). Males are solitary and fiercely territorial. Females are generally less ornate but can be kept in 'sororities' with strict precautions (minimum 5 females in 75L+).
Mexican Dwarf Crayfish (CPO)
Cambarellus patzcuarensis
A highly entertaining, fully aquatic dwarf crayfish. In the aquarium trade, the bright orange 'CPO' morph is the most popular. Unlike larger crayfish, they are generally safe with plants and fast-moving mid-to-top dwelling fish. However, they are opportunistic omnivores with claws; they will hunt dwarf shrimp and may nip the fins of slow, long-finned bottom dwellers.
Schooling Fish
Active swimmers best kept in groups. They bring movement and colour to the mid and upper levels of your tank.
Chili Rasbora
Boraras brigittae
A striking, deeply red nano fish native to the blackwater streams and peat swamps of southern Borneo. They are extremely peaceful and require a mature, densely planted aquarium with soft, acidic water. Due to their tiny size, they are completely safe with adult dwarf shrimp and are ideal for nano setups.
Clown Killifish
Epiplatys annulatus
A striking nano killifish resembling a tiny rocket. Native to West African swamps, they have distinct black and yellow vertical bands. They are strictly surface dwellers (top-level) and are non-annual, meaning they live longer than annual killifish (2-3+ years). They are notorious jumpers and require a tight lid.
Japanese Ricefish (Medaka)
Oryzias latipes
A hardy, small, and colorful fish native to East Asia. Extremely popular in the outdoor pond hobby and nano aquariums. They are 'amphidromous' (tolerant of salinity changes) and can survive a wide range of temperatures, making them excellent tub/pond fish. They are surface dwellers that look best when viewed from above (top-down).
Bottom Dwellers
Species that inhabit the lower reaches of the aquarium, helping keep the substrate clean and adding activity to the tank floor.
Assassin Snail
Clea helena
A highly effective and popular carnivorous freshwater snail used primarily for pest snail control. They actively hunt and consume smaller snails like bladder, ramshorn, and pond snails. Featuring a striking yellow and dark brown spiraled shell, they are a functional and attractive addition to aquariums. Unlike many aquatic snails, they are not hermaphroditic and reproduce quite slowly.
Bee Shrimp (Crystal Red / Black)
Caridina cantonensis
A sensitive, highly prized dwarf shrimp species known for its vivid red/white or black/white banding. Unlike the hardy Cherry Shrimp (Neocaridina), Bee Shrimp require cool, soft, acidic water and typically require active buffering soil to thrive. They are peaceful grazers perfect for specific biotope setups.
Bladder Snail (Pest Snail)
Physella acuta
A tiny, fast-moving freshwater snail almost universally introduced accidentally via live aquarium plants. While frequently labeled a 'pest' due to their rapid, prolific reproduction, they are actually an excellent cleanup crew. They consume algae, uneaten food, and decaying plant matter without harming healthy plants. They are hermaphroditic and can self-fertilize, meaning a single snail can start a massive colony.
Cherry Shrimp
Neocaridina davidi
One of the most popular and hardy freshwater invertebrates in the hobby. They come in a rainbow of selectively bred colors. They are excellent scavengers and algae eaters, perfect for nano planted tanks. They are completely peaceful and have a negligible bioload, though they are highly vulnerable to predation by almost any fish with a mouth large enough to eat them.
Ghost Shrimp
Palaemonetes paludosus
A completely transparent freshwater shrimp native to the southeastern United States. While frequently sold as inexpensive feeder animals, they make fascinating, active scavengers for nano and peaceful community tanks. They tirelessly consume uneaten food and detritus but have a relatively short lifespan of 1 to 2 years.
Least Killifish (Heterandria)
Heterandria formosa
Despite its common name, the Least Killifish is actually one of the smallest livebearing fish in the world, belonging to the Poeciliidae family, not the killifish family. Native to the southeastern United States, they are incredibly peaceful and perfect for nano tanks. Unlike most livebearers, they exhibit 'superfoetation', meaning females drop 1-2 fry every few days rather than a large single brood.
Other Compatible Species
Additional species that are compatible with this tank size but don't fall neatly into the categories above.
Frequently Asked Questions — 5 Gallon
How many fish can I put in a 5 Gallon?
The 5 Gallon (19 L / 5 gal) is compatible with 18 species in our database. The actual number of individual fish depends on the species mix — use the stocking recipes above as a starting point and aim to keep the total bioload below 85% of capacity.
What is the best centrepiece fish for a 5 Gallon?
Popular centrepiece options for this tank include Betta (Siamese Fighting Fish), Mexican Dwarf Crayfish (CPO). A centrepiece fish should be the focal point of your aquarium — choose one with colours and behaviour that complement your other species.
What schooling fish work in a 5 Gallon?
Great schooling options include Chili Rasbora, Clown Killifish, Japanese Ricefish (Medaka). Schooling fish should be kept in groups of at least 6 to encourage natural behaviour and reduce stress.
What bottom dwellers suit a 5 Gallon?
Suitable bottom dwellers include Assassin Snail, Bee Shrimp (Crystal Red / Black), Bladder Snail (Pest Snail). These species occupy the lower zone of your tank, helping to keep the substrate tidy and adding activity to an often-overlooked area.
What temperature should a 5 Gallon be?
The ideal temperature depends on the species you keep. Most tropical freshwater fish thrive between 24–27°C (75–80°F). Check each species' requirements and aim for the overlapping range that suits all your inhabitants.