Plan before you buy

Plan Your Aquarium With Confidence

Size the tank, choose the right fish, and check they get along — using calculators and species data that show their work, not just a number.

Quick Planning

Volume, substrate, heater, filter, water changes and more — with the math explained.

Browse species profiles with adult size, tank minimums, and water parameters.

See whether two species can share a tank — chemistry, temperament, and size.

Assemble your tank, fish, and equipment into one plan with warnings.

Calculate tank capacity in US gallons and liters, plus actual water volume.

Plan how many fish your tank can support with a proper stocking assessment.

Work out how much substrate (gravel, sand, or soil) your tank needs.

Calculate gravel amount and weight for your tank size and depth.

Estimate total tank weight: water, glass, substrate, decor, and equipment.

Find the right heater wattage range for your tank and room temperature.

Size your filter flow rate based on tank volume and turnover rate.

Calculate how much water to remove and replace during a water change.

Match a species (and school size) to the right tank dimensions.

Check compatibility between any two species in our database — temperature, water chemistry, temperament, and adult size all considered.