Check how many fish your tank can support by the inch-per-gallon rule.
Dividing tank gallons by each fish's adult length gives a rough ceiling, a simplified but widely used planning rule. Overstocking spikes waste and ammonia, so a quick estimate keeps the bioload in line with filtration.
Aquarium Stocking
Max fish = tank gallons / inches per adult fish
Max fish = tank gallons / inches per adult fish Dividing tank gallons by each fish's adult length gives a rough ceiling, a simplified but widely used planning rule.
Overstocking spikes waste and ammonia, so a quick estimate keeps the bioload in line with filtration.
This calculator takes 2 inputs: Tank volume, Adult fish size. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.