Fish Stocking: A Rough Rule, Not a Guarantee
The one-centimetre-per-litre rule gives beginners a starting limit. It cannot capture temperament, waste load, or swimming space, so it should never be pushed to the edge.
What is the Fish Stocking Calculator?
Enter tank volume and adult fish size, and the tool estimates a maximum count from the simple guide of one centimetre of adult fish per litre. This is a rough starter guide, not expert advice, since species, filtration, and behaviour change safe stocking a great deal.
How to use it
- Enter tank volume in litres.
- Pick adult fish size.
- Click Estimate Fish Stocking.
Worked example
For a 72-litre tank and 3 cm adult fish, the guide maximum is 24 fish.
Can I stock to the maximum?
Stocking below the maximum is safer, especially in a new tank where filtration is still maturing.
Frequently asked questions
Is this expert advice?
No. It is a starter guide. Species-specific research matters more than any single rule.
Do plants change stocking?
Plants help water quality, but they do not turn an overstocked tank into a safe one.