Aquarium Stocking Calculator
Add your tank size and the fish you're planning, and we'll calculate your true stocking level and filtration load, then flag compatibility problems — tank too small, schooling fish kept in too-small groups, fin-nippers, predators, and temperature/pH mismatches.
Frequently Asked Questions
How does the stocking calculator work?
It compares total bioload (a per-species waste weight) against your tank's capacity, which scales with usable water volume and filter turnover. It also runs species-specific checks for minimum tank size, schooling group size, temperament conflicts, and overlapping temperature and pH ranges.
What stocking percentage should I aim for?
Under ~90% is comfortable for most keepers. Up to 100% is workable with strong filtration and consistent water changes. Over 100% means you should reduce numbers, upgrade tank size, or add filtration.
Why does it warn about schooling fish?
Schooling species like tetras, rasboras, and corydoras become stressed, nippy, and short-lived when kept in groups that are too small. Keep them in their recommended minimum group or more.