Pet
Fish Tank Stocking (Rough) Calculator
Roughly estimate total fish length a tank can support using the inch-per-gallon guide.
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Formula
Total fish length in centimetres equals US gallons multiplied by 2.54, from the one-inch-per-gallon rule.
How it works
Tank litres convert to US gallons, and each gallon is allowed one inch of adult fish length. The rule ignores species behaviour, waste, filtration and shape, so it is only a first sanity check.
FAQs
Should I stock to this limit?
Stay below it, especially as a beginner; filtration and maintenance matter.
Does adult size count?
Yes. Always use adult size, not the size at purchase.
Do plants change it?
Plants help water quality but do not make the rule exact.
General information only, not veterinary advice.
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