Fish Tank Stocking Calculator
Plan a healthy aquarium by estimating how many fish of a given size your tank can comfortably support.
Recommended Max Fish Count
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Adjusted Inch Capacity—
Theoretical Max Fish—
Recommended Safe Count—
About this calculator
Determine how many fish your aquarium can safely hold based on tank volume, fish size, and bioload preferences.
Frequently Asked Questions
Is the 'inch per gallon' rule accurate?
It's a rough starting guideline, best for small, similarly-shaped fish. Larger, waste-heavy, or territorial species need much more space than the rule suggests.
Why does filtration matter for stocking?
Better filtration processes waste and ammonia faster, allowing a slightly higher bioload without harming water quality.
Should I stock at the maximum number?
No, it's best to stay below the calculated maximum to leave a safety margin for growth, waste buildup, and breeding.