Estimate how many fish a tank can safely stock.
The classic one-inch-of-fish-per-gallon rule gives a total fish length the tank can support, which divides by average adult size for a fish count. Overstocking raises waste and oxygen demand, so matching fish to filter and water volume prevents chronic water-quality problems.
Fish Tank Stocking
Stocking = tank gallons x inches per gallon
Stocking = tank gallons x inches per gallon The classic one-inch-of-fish-per-gallon rule gives a total fish length the tank can support, which divides by average adult size for a fish count.
Overstocking raises waste and oxygen demand, so matching fish to filter and water volume prevents chronic water-quality problems.
This calculator takes 3 inputs: Tank size, Inches per gallon, Avg adult fish length. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.