Fish Tank Stocking Calculator
Overstocking is one of the most common aquarium mistakes. Enter your tank volume and typical fish size to get an estimated safe stocking capacity.
Estimated Safe Fish Count
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Base inch capacity (1 gal/inch rule)—
Bioload adjustment factor—
Adjusted capacity (inches)—
About this calculator
Estimate how many fish your aquarium can safely support based on tank size, fish size, and bioload factors.
Frequently Asked Questions
What is the 'inch per gallon' rule?
A common rough guideline suggesting 1 inch of adult fish per gallon of water, though it's not perfect for all species.
Why does bioload matter?
Some fish (like goldfish or large cichlids) produce far more waste per inch than small schooling fish, requiring more effective volume per fish.
Should I trust this for saltwater tanks?
This is a general freshwater guideline. Saltwater reef tanks typically need much lower stocking density.