Choose the fish, shrimp, snails or frogs you want to keep and get the tank they need: a minimum, a recommended range for your experience, the length and height, and a standard tank that fits. It covers more than 150 freshwater, brackish and saltwater species, plus fish that are not listed.
1. Choose your fish
Aquarium type
Add one or more species to see the tank size they need.
Your list is shared with the stocking calculator and compatibility checker on this device.
2. About you and your tank
Your experience
Are you choosing a new tank?
More options: decor and breeding
Rocks, wood and plants
Recommended tank size
Add a species above to see the recommendation.
Minimum tank size chart (154 species)
Group
Temperature
Care
African dwarf frogHymenochirus boettgeriFully aquatic but breathes air: keep the water shallow enough to reach the surface. Slow feeders.
1.4 in
5 gal
16 in
2+
72–82 °F
Easy
Assassin snailAnentome helenaHunts other snails, including nerites and mystery snails. Harmless to fish and adult shrimp.
1 in
5 gal
16 in
Alone or more
72–82 °F
Easy
Betta (Siamese fighting fish)Betta splendensOne male per tank. OATA: at least 20 L for a male, 60 L for a group of females.
2.6 in
5 gal
16 in
One per tank
75–86 °F
Easy
Blue dream shrimpNeocaridina davidi (blue)A colour form of the cherry shrimp: keep one colour per tank to keep the colour line.
1.2 in
5 gal
16 in
10+
64–81 °F
Easy
Cherry shrimpNeocaridina davidiHardy and breeds readily in a mature, planted tank.
1.2 in
5 gal
16 in
10+
64–81 °F
Easy
Chili rasboraBoraras brigittae
0.8 in
5 gal
16 in
10+
68–82 °F
Moderate
Crystal black shrimpCaridina cantonensisSame needs as crystal red shrimp, and the two interbreed.
1 in
5 gal
16 in
10+
64–75 °F
Expert
Crystal red shrimpCaridina cantonensisNeeds soft, acidic water: RO water with a shrimp remineraliser and an active soil.
1 in
5 gal
16 in
10+
64–75 °F
Expert
Malaysian trumpet snailMelanoides tuberculataBurrows and turns over the sand; breeds quickly.
1 in
5 gal
16 in
Alone or more
64–86 °F
Easy
Mystery snailPomacea diffusaNeeds hard water for a healthy shell. Lays egg clutches above the waterline.
2 in
5 gal
16 in
Alone or more
68–82 °F
Easy
Nerite snailNeritina spp.Excellent algae eater. Its white eggs do not hatch in fresh water.
1 in
5 gal
16 in
Alone or more
72–81 °F
Easy
Ramshorn snailPlanorbella duryiBreeds quickly when there is plenty of food.
1 in
5 gal
16 in
Alone or more
64–82 °F
Easy
Clown killifishEpiplatys annulatus
1.4 in
8 gal
18 in
6+
72–82 °F
Moderate
Endler's livebearerPoecilia wingei
1.2 in
8 gal
18 in
3+
75–86 °F
Easy
Ghost shrimpPalaemonetes paludosusCheap and hardy; may eat very small fry.
1.6 in
8 gal
18 in
5+
64–82 °F
Easy
Sparkling gouramiTrichopsis pumila
1.6 in
8 gal
18 in
4+
72–82 °F
Easy
Sulawesi cardinal shrimpCaridina dennerliNeeds very warm, stable water matched to Sulawesi lakes: best in a species-only tank.
1 in
8 gal
18 in
10+
81–86 °F
Expert
African clawed frogXenopus laevisEats anything that fits in its mouth: keep without fish. Restricted in some regions, so check local law.
4.7 in
11 gal+ 5 gal per extra
18 in
Alone or more
64–75 °F
Easy
Amano shrimpCaridina multidentataA strong algae eater. Larvae need brackish water, so they do not breed in a normal aquarium.
2 in
11 gal
18 in
5+
64–81 °F
Easy
Bumblebee gobyBrachygobius doriaeBrackishTerritorial over caves; usually takes only live or frozen food.
1.2 in
11 gal
18 in
6+
72–84 °F
Moderate
Celestial pearl danioDanio margaritatus
1 in
11 gal
18 in
8+
68–79 °F
Moderate
Ember tetraHyphessobrycon amandae
0.8 in
11 gal
18 in
10+
75–82 °F
Easy
GuppyPoecilia reticulataBreeds readily: plan for fry.
2 in
11 gal
18 in
3+
72–82 °F
Easy
Honey gouramiTrichogaster chuna
2 in
11 gal
18 in
Alone or more
72–82 °F
Easy
Medaka (Japanese rice fish)Oryzias latipesUnheated tanks are fine indoors.
1.6 in
11 gal
18 in
6+
61–79 °F
Easy
Mexican dwarf crayfishCambarellus patzcuarensisSafe with most fast fish; may catch baby shrimp and fish that rest on the bottom.
1.6 in
11 gal
18 in
Alone or more
64–79 °F
Easy
Pea puffer (dwarf puffer)Carinotetraodon travancoricusBest in a species-only tank; eats snails and shrimp.
1.2 in
11 gal
18 in
Alone or more
75–82 °F
Moderate
Pygmy corydorasCorydoras pygmaeus
1 in
11 gal
18 in
8+
72–79 °F
Easy
White cloud mountain minnowTanichthys albonubesA cool-water fish: no heater needed in most homes.
AxolotlAmbystoma mexicanumA cool-water salamander: keep it at 16–18 °C and never above 24 °C (RVC). Keep without fish, which nip its gills or get eaten, and use fine sand or a bare floor so it cannot swallow gravel.
9.1 in
21 gal
31 in
Alone or more
61–64 °F
Moderate
Bamboo shrimpAtyopsis moluccensisFilter-feeds with fans held in the current: needs steady flow and a mature tank.
3.1 in
21 gal
24 in
Alone or more
73–82 °F
Moderate
Black skirt tetraGymnocorymbus ternetzi
2.4 in
21 gal
31 in
6+
72–82 °F
Easy
Bloodfin tetraAphyocharax anisitsi
2.2 in
21 gal
31 in
8+
64–82 °F
Easy
Cardinal tetraParacheirodon axelrodiWarmer and softer water than neons; a good match for discus.
1.6 in
21 gal
31 in
10+
73–84 °F
Moderate
Clown plecoPanaqolus maccusRasps on wood as part of its diet: include driftwood.
3.5 in
21 gal
24 in
Alone or more
73–82 °F
Easy
Electric blue crayfishProcambarus alleniCatches fish, eats plants and climbs out of open tanks. Some crayfish are restricted: check local rules.
4.7 in
21 gal
31 in
One per tank
68–79 °F
Easy
KribensisPelvicachromis pulcherBecomes territorial when breeding.
3.9 in
21 gal
31 in
Alone or more
75–81 °F
Easy
Kuhli loachPangio kuhliiSlender body: low waste for its length. Likes soft sand.
3.9 in
21 gal
31 in
5+
75–86 °F
Easy
Lemon tetraHyphessobrycon pulchripinnis
2 in
21 gal
31 in
8+
72–82 °F
Easy
Paradise fishMacropodus opercularis
3.9 in
21 gal
31 in
One per tank
61–79 °F
Easy
Pearl danioDanio albolineatusFast swimmers that need open swimming space along the front of the tank.
2.4 in
21 gal
31 in
6+
68–77 °F
Easy
Reticulated hillstream loachSewellia lineolataNeeds strong flow and high oxygen.
2.4 in
21 gal
31 in
3+
68–75 °F
Moderate
Serpae tetraHyphessobrycon eques
1.8 in
21 gal
31 in
8+
72–82 °F
Easy
Sterbai corydorasCorydoras sterbaiHandles warmer water than most corydoras, so often kept with discus or rams.
3.1 in
21 gal
31 in
6+
75–82 °F
Easy
Zebra danioDanio rerioVery active; prefers a long tank.
2 in
21 gal
31 in
6+
64–77 °F
Easy
African butterfly fishPantodon buchholziA surface hunter: eats small fish at the top and jumps if the lid is loose.
3.9 in
26 gal
31 in
Alone or more
75–86 °F
Moderate
Bolivian ramMikrogeophagus altispinosus
3.1 in
26 gal
31 in
Alone or more
72–79 °F
Easy
Bristlenose plecoAncistrus sp.
5.1 in
26 gal
31 in
Alone or more
72–81 °F
Easy
Celebes rainbowfishMarosatherina ladigesi
2.8 in
26 gal
31 in
6+
72–82 °F
Moderate
Dwarf chain loachAmbastaia sidthimunki
2.2 in
26 gal
31 in
6+
75–82 °F
Easy
Dwarf neon rainbowfishMelanotaenia praecox
2.4 in
26 gal
35 in
6+
75–82 °F
Easy
Figure 8 pufferDichotomyctere ocellatusBrackishLow-end brackish water. Needs snails and hard foods to wear down its teeth.
3.1 in
26 gal
31 in
One per tank
75–82 °F
Moderate
Glass catfishKryptopterus vitreolus
3.1 in
26 gal
31 in
6+
75–82 °F
Moderate
Gold barbBarbodes semifasciolatus
2.8 in
26 gal
31 in
6+
64–75 °F
Easy
Goldfish (fancy)Carassius auratusWill eat any fish small enough to swallow. OATA: at least 100 L for one adult plus 50 L per extra adult. Heavy waste producers.
7.9 in
26 gal+ 13 gal per extra
31 in
2+
59–75 °F
Easy
Odessa barbPethia padamyaMay nip long fins if kept in too small a group.
2.8 in
26 gal
31 in
6+
68–79 °F
Easy
Red-eye tetraMoenkhausia sanctaefilomenae
2.8 in
26 gal
31 in
6+
72–82 °F
Easy
Rummy-nose tetraHemigrammus rhodostomus
2 in
26 gal
31 in
10+
75–88 °F
Moderate
Silver hatchetfishGasteropelecus sterniclaStrong jumpers: needs a tight lid.
2.6 in
26 gal
31 in
6+
73–81 °F
Moderate
Tiger barbPuntigrus tetrazonaGroups of 6+ nip each other rather than tankmates; still avoid long-finned fish.
2.8 in
26 gal
31 in
6+
68–79 °F
Easy
Upside-down catfishSynodontis nigriventris
3.5 in
26 gal
31 in
5+
72–82 °F
Easy
Vampire shrimpAtya gabonensisA large, harmless filter feeder that needs current.
5.9 in
26 gal
31 in
Alone or more
73–82 °F
Moderate
Banggai cardinalfishPterapogon kauderniSaltwater
3.1 in
29 gal
31 in
Alone or more
73–81 °F
Easy
Green chromisChromis viridisSaltwater
3.1 in
29 gal
39 in
5+
72–81 °F
Easy
Lawnmower blennySalarias fasciatusSaltwater
5.1 in
29 gal
31 in
One per tank
72–81 °F
Moderate
Mandarin dragonetSynchiropus splendidusSaltwaterEats tiny live copepods all day: only for a mature reef with a large live-rock population.
2.8 in
29 gal
31 in
One per tank
72–81 °F
Expert
Molly (common or sailfin)Poecilia sphenops / P. latipinnaPrefers hard, alkaline water; tolerates brackish.
Flame angelfishCentropyge loriculaSaltwaterMay nip soft corals and clam mantles.
3.9 in
70 gal
47 in
One per tank
72–81 °F
Moderate
Foxface rabbitfishSiganus vulpinusSaltwaterVenomous fin spines: handle with care. Grazes algae.
9.4 in
70 gal
59 in
One per tank
72–81 °F
Easy
Kole tangCtenochaetus strigosusSaltwater
7.1 in
70 gal
47 in
One per tank
72–81 °F
Moderate
Bluestreak cleaner wrasseLabroides dimidiatusSaltwaterCleaner wrasses feed on parasites picked from other fish and most starve in home aquariums. Leave them on the reef.
4.3 in
Not for home tanks
47 in
One per tank
73–81 °F
Expert
Copperband butterflyfishChelmon rostratusSaltwaterOften hard to wean onto prepared food; picks at tube worms and some corals.
7.9 in
75 gal
47 in
One per tank
73–81 °F
Expert
Denison barb (roseline shark)Sahyadria denisonii
5.9 in
79 gal
59 in
6+
59–77 °F
Moderate
DiscusSymphysodon spp.Needs very warm, clean water and frequent large water changes.
5.9 in
79 gal
47 intall tank
5+
82–88 °F
Expert
Elephantnose fishGnathonemus petersiiShy and sensitive; feeds on live or frozen worms in dim light. Squabbles with its own kind.
9.1 in
79 gal
47 in
One per tank
73–82 °F
Expert
Jack DempseyRocio octofasciata
9.8 in
79 gal
47 in
Alone or more
72–86 °F
Moderate
Peacock cichlidAulonocara spp.
5.9 in
79 gal
47 in
Alone or more
75–82 °F
Moderate
Rainbow sharkEpalzeorhynchos frenatum
5.9 in
79 gal
47 in
One per tank
72–81 °F
Moderate
Red-tail sharkEpalzeorhynchos bicolorTerritorial towards similar-looking fish.
5.9 in
79 gal
47 in
One per tank
72–79 °F
Moderate
RopefishErpetoichthys calabaricusAn escape artist: seal every gap in the lid.
15.7 in
79 gal
47 in
Alone or more
72–82 °F
Moderate
Senegal bichirPolypterus senegalus
11.8 in
79 gal
47 in
Alone or more
75–84 °F
Easy
SeverumHeros severus
7.9 in
79 gal
47 in
Alone or more
73–84 °F
Moderate
Silver dollarMetynnis argenteus
5.9 in
79 gal
59 in
5+
75–82 °F
Moderate
Yoyo loachBotia almorhae
5.9 in
79 gal
47 in
5+
72–82 °F
Moderate
Yellow tangZebrasoma flavescensSaltwaterNeeds open swimming space and plenty of algae in the diet.
7.9 in
100 gal
59 in
One per tank
72–81 °F
Moderate
Chinese algae eaterGyrinocheilus aymonieriBecomes territorial with age and may latch onto slow, flat-sided fish.
11 in
106 gal
59 in
One per tank
68–82 °F
Moderate
Common or comet goldfishCarassius auratusFast, long-bodied goldfish that outgrow most aquariums; a pond suits them best.
11.8 in
106 gal
59 in
2+
39–75 °F
Easy
Flowerhorn cichlidHybrid (Amphilophus and others)Very aggressive hybrid: usually kept alone.
11.8 in
106 gal
59 in
One per tank
79–86 °F
Moderate
Green terrorAndinoacara rivulatus
9.8 in
106 gal
59 in
Alone or more
68–79 °F
Moderate
Kissing gouramiHelostoma temminckiiThe "kissing" is sparring between rivals. Grows much larger than most gouramis.
7.9 in
119 gal
59 in
Alone or more
72–82 °F
Moderate
Volitan lionfishPterois volitansSaltwaterVenomous spines; swallows any fish or shrimp that fits in its mouth.
15 in
120 gal
71 in
One per tank
72–81 °F
Moderate
Powder blue tangAcanthurus leucosternonSaltwaterProne to white spot (marine ich) and aggressive to other tangs.
FrontosaCyphotilapia frontosaLake Tanganyika cichlid usually kept as a colony; eats any fish small enough to swallow.
11.8 in
159 gal
71 in
Alone or more
75–81 °F
Moderate
Tire track eelMastacembelus armatusBurrows in sand and eats small fish; grows long.
23.6 in
159 gal
71 in
One per tank
72–82 °F
Moderate
Humu Picasso triggerfishRhinecanthus aculeatusSaltwaterNot reef safe: eats shrimp, crabs and small fish and moves loose rock. LiveAquaria: 180 US gal minimum, 72–78 °F.
9.8 in
180 gal
71 in
One per tank
72–78 °F
Moderate
Regal blue tangParacanthurus hepatusSaltwater
11.8 in
180 gal
71 in
One per tank
72–81 °F
Expert
Clown loachChromobotia macracanthusGrows slowly but eventually very large; needs a big tank long term.
11.8 in
185 gal
71 in
5+
77–86 °F
Moderate
Common plecoPterygoplichthys / Hypostomus spp.Sold small but grows to 45 cm or more and produces heavy waste.
17.7 in
198 gal
71 in
One per tank
72–82 °F
Moderate
Bala sharkBalantiocheilos melanopterusA fast shoaling fish that reaches about 35 cm: needs a very long tank and a lid.
13.8 in
396 gal
94 in
5+
72–82 °F
Moderate
Tinfoil barbBarbonymus schwanenfeldiiSold at a few centimetres but grows to about 35 cm in a shoal: a very large tank long term.
13.8 in
396 gal
94 in
5+
72–82 °F
Moderate
KoiCyprinus rubrofuscusPond fish: grows far too large for aquariums.
27.6 in
Pond
–
3+
39–77 °F
Moderate
Minimum tank is for a sensible group of that species (or one animal if it lives alone), not for a mixed community. Minimum length comes from care-sheet base dimensions where given, otherwise from the length of a standard tank of that volume.
Quick answer
Tank size depends on the adult size, activity, group size and shape of every species you keep, not on one rule. A betta needs at least 20 L (5 gal); 10 neon tetras with 6 corydoras need about 80 L (21 gal); two fancy goldfish need 150 L (40 gal) (OATA); freshwater angelfish need about 200 L (53 gal) in a tank at least 45 cm tall; an oscar needs 500 L (132 gal) and a tank about 150 cm long. Koi and common goldfish belong in a pond.
How the guide works out tank size
The guide takes the largest of two numbers. The first is the care-sheet minimum for each species, kept as a proper group (for example, 10 neon tetras rather than 1). The second is a stocking estimate for all your animals together: about 1 litre of water per centimetre of adult fish, weighted up for heavy-waste fish such as goldfish, plecos and oscars and down for shrimp and snails.
It then checks shape. Fast swimmers need a long tank, so each species has a minimum tank length. Tall-bodied fish such as angelfish and discus also need a tank at least 45 cm tall. The suggested standard tank must meet the volume, the length and the height; litres alone are never enough.
Finally it adds headroom for your experience: 25–75% above the minimum for beginners, 10–50% for intermediate keepers and up to 30% for experienced keepers. Heavy rock and wood add 10%, and breeding livebearers or cichlids adds 20%. These margins are our guidance, not a published standard.
Why there is no single stocking percentage
Rules such as “1 inch per gallon” fail for big, messy or territorial fish. That is why the guide uses each species’ own minimum and length, and warns about groups, temperature, pH and fish that eat each other.
Worked examples
Results from the guide for a beginner, metric tanks
For the neon and corydoras tank, the stocking estimate for both species together (77 L) is larger than either care-sheet minimum, so it sets the minimum.
Minimum tank size for popular fish
Smallest suitable tank for a group (or one animal if kept alone)
Species
Adult size
Minimum tank
Group
Betta (male)
6.5 cm
20 L (5 gal)
Alone
Cherry shrimp
3 cm
20 L (5 gal)
10+
Guppy
5 cm
40 L (11 gal)
3+
Neon tetra
3.5 cm
54 L (14 gal)
10+
Harlequin rasbora
4.5 cm
60 L (16 gal)
8+
Bronze corydoras
7 cm
60 L (16 gal)
6+
Tiger barb
7 cm
100 L (26 gal)
6+
Fancy goldfish
20 cm
100 L + 50 L per extra fish
2+
Freshwater angelfish
15 cm
200 L (53 gal), 45 cm tall
1+
Discus
15 cm
300 L (79 gal), 45 cm tall
5+
Oscar
35 cm
500 L (132 gal)
1+
Ocellaris clownfish
8 cm
75 L (20 gal)
1–2
Koi
70 cm
Pond (4,000 L+)
3+
Compiled from Seriously Fish, FishBase, OATA care sheets and LiveAquaria. Gallons are US gallons, rounded. The full chart below the tool lists every species.
Why bigger and longer tanks are easier
More water dilutes waste, so ammonia and nitrite rise more slowly and temperature changes are gentler. That makes larger tanks more forgiving for beginners, not harder.
Shape matters too. Active swimmers such as danios and rainbowfish need length; tall fish such as angelfish need height; bottom dwellers such as corydoras need floor space. Two tanks with the same volume can suit very different fish, which is why the guide gives a length and height as well as litres.
Shrimp, snails, frogs and crayfish
Invertebrates need little space but have their own rules. Most fish over about 8 cm will eat baby shrimp, and many loaches, puffers and cichlids eat snails. Assassin snails hunt other snails. Copper in medicines and some plant foods is toxic to shrimp and snails, and crayfish climb out of tanks without a tight lid.
Cherry and blue dream shrimp are both Neocaridina and interbreed, as do crystal red and crystal black shrimp. The guide warns you about each of these when you add them together.
Tank size guide vs volume calculator
This guide answers what size tank your fish need. The aquarium volume calculator answers how much water a tank actually holds once you subtract glass, gravel and decor. Use this guide to choose a tank, then the volume calculator to confirm its real capacity.
The goldfish bowl myth
Goldfish grow to 20 cm or more and produce a lot of waste. OATA recommends at least 100 litres for one adult fancy goldfish plus 50 litres for each extra fish, with good filtration. Common and comet goldfish grow longer still and are best kept in ponds.
No bowls
Small bowls cannot hold enough water or a proper filter for any fish, including bettas and goldfish.
Frequently asked questions
What is the best tank size for beginners?+
Around 60–100 litres (15–30 US gallons). It is small enough to manage but large enough to stay stable, and suits most community fish.
What size tank does a betta need?+
At least 20 litres (5 US gallons) for one male, with a heater and gentle filter. A group of females needs at least 60 L.
How big a tank do I need for 2 goldfish?+
For fancy goldfish, OATA recommends at least 100 L for the first and 50 L for each extra, so 150 L (about 40 US gallons) for two.
Can I keep a fish in a smaller tank while it is young?+
Only briefly, and only if you already have the adult tank planned. Fish grow quickly, and stunting from a small tank harms their health.
Does tank shape matter?+
Yes. Long tanks give more swimming room and surface area for oxygen; tall tanks suit tall-bodied fish like angelfish but hold less surface area per litre. The guide gives a minimum length for every species and a minimum height for tall-bodied fish.
Is the “1 inch of fish per gallon” rule accurate?+
Only roughly, for small community fish. It badly underestimates the space needed by large, messy or territorial fish such as goldfish, plecos and cichlids, so the guide also uses each species’ own minimum tank and length.
What size tank do cherry shrimp need?+
A colony of 10 or more can live in 20 L (5 gal), but 40 L or more is more stable. Keep them away from fish over about 8 cm, which eat baby shrimp, and never use medicines containing copper.
What if my fish is not listed?+
Choose “Other / not listed” in the species search and enter its adult size. The guide estimates space from its size, but check a species profile on Seriously Fish or FishBase for its group, temperature and water needs.
Disclaimer: Minimum sizes are guides for healthy adult fish. Larger tanks are always better, and some individuals or breeding pairs need more space. See our disclaimer.
