CALCULATOR
Stocking Density
How many fish fit your tank — 1 inch of fish per gallon, adjusted for real-world stocking.
9
fish
≈ 14.0 inches of fish · 2.2 gal each
Stocking rules of thumb
| Fish | Adult size | Min tank |
|---|---|---|
| Neon tetra | 1.5 in | 10 gal (school of 6+) |
| Betta | 2.5 in | 5 gal |
| Guppy | 2 in | 10 gal |
| Fancy goldfish | 6-8 in | 20 gal each |
Never stock for purchase size — always adult size. See the full stocking guide.