Aquarium tools

Free, instant calculators built on published species data. No signup, and never any ads inside the tools.

• Tank volume calculatorLiters and US gallons from your tank's dimensions — rectangular, bow-front, cylinder or corner.
• Stocking calculatorA live fill percentage and a compatibility verdict for every pair of fish, with the reason for each.
• Fish compatibilityInstant matrix showing which fish, shrimp, and snails can live together — with reasons.
• Water change calculatorHow many liters to replace at your chosen percentage.
• Substrate calculatorGravel or sand volume, weight and number of bags.

More tools are on the way: a printable compatibility matrix, water-change, substrate and cycling calculators.