🐟 Aquarium Stocking Calculator
Calculate your tank volume and find safe stocking levels using both the surface area rule and the classic inch-per-gallon guide. Includes a popular fish reference table.
Tank Dimensions
Popular Fish Reference
| Fish | Type | Adult Size | Min Tank | Compatibility | Notes |
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About Aquarium Stocking
The surface area rule is based on the idea that oxygen enters the water at the surface — the larger the surface, the more dissolved oxygen is available. A rough guide is 12 cm² of water surface per 1 cm of adult fish length for freshwater, and 10 cm² per 1 cm for saltwater (marine fish are generally more sensitive).
The 1 inch per gallon rule was popularised in the mid-20th century but is now considered a starting point at best. A 10-inch goldfish needs far more care than ten 1-inch tetras. Always research each species individually.
Good filtration, regular water changes (25% weekly), adequate surface agitation, and compatible species are more important than hitting an exact number.