Aquarium Stocking Calculator
Free tools for freshwater fishkeepers — a species-aware stocking estimate, a tank volume calculator, and a sourced species reference chart.
Before you stock a tank: the stocking calculator is a rough guide based on a widely-used rule-of-thumb heuristic, not a scientific verdict. It doesn’t replace testing your water, cycling your tank first, or researching whether your specific fish get along. See the stocking calculator page for the full caveats.
Stocking / bioload calculator
Enter your tank size and fish list — get a rough, species-aware stocking estimate with minimum-tank-size and minimum-school-size checks.
Tank volume calculator
Enter your tank's dimensions (rectangular or cylindrical) — get gross and estimated usable volume in gallons and liters.
Fish species reference chart
Sourced adult size, minimum tank size, minimum group size, relative bioload, and temperament for common freshwater species.