How many fish in a 10 gallon tank?
Short answer: roughly 10 small, slim fish (like neon tetras or rasboras) in a well-filtered 10 gallon tank — far fewer if they grow larger. Good options: Betta fish, Ember tetra.
Tested stocking ideas
Betta community
1 × Betta fish, 6 × Panda cory, 1 × Nerite snail
Nano schooling tank with shrimp
8 × Ember tetra, 8 × Pygmy cory, 10 × Cherry shrimp
Species that fit a 10 gallon tank
| Species | How many (alone) | Note |
|---|---|---|
| Betta fish | 1 | one male |
| Cherry shrimp | up to 99 | groups of 10+ |
| Dwarf gourami | 1 | one male |
| Guppy | up to 8 | groups of 3+ |
| Amano shrimp | up to 42 | groups of 3+ |
| Celestial pearl danio | up to 34 | groups of 6+ |
| Chili rasbora | up to 47 | groups of 8+ |
| Ember tetra | up to 41 | groups of 8+ |
| Endler's livebearer | up to 22 | groups of 3+ |
| Mystery snail | up to 21 | |
| Nerite snail | up to 99 | |
| Otocinclus | up to 16 | groups of 6+ |
| Panda cory | up to 8 | groups of 6+ |
| Pea puffer | up to 22 | |
| Pygmy cory | up to 26 | groups of 8+ |
| Sparkling gourami | up to 11 |
How we calculate it
We count each fish in "units": one slim 5 cm (2 inch) fish = 1 unit, and a well-filtered tank holds about 1 unit per US gallon. Units scale with (adult length ÷ 5 cm)1.5 × a body-mass factor, so a 15 cm angelfish counts as about 8 units, not 3. Species are excluded if their recommended minimum tank is larger than 10 gallons.
Other sizes: 5 gallon · 20 gallon · 29 gallon · 40 gallon · 55 gallon · 75 gallon
FAQ
How many fish can I put in a 10 gallon tank?
It depends on the species. As a conservative guide, a 10 gallon tank holds about 10 small (2 inch) slim fish, far fewer large or heavy-bodied fish. The table above lists the maximum for each suitable species kept on its own.
Is the 1 inch per gallon rule accurate?
Only for small, slim fish. Waste output grows much faster than length, so a 6 inch fish produces far more waste than three 2 inch fish. We scale by body size and body shape instead.