Tools
Aquarium calculators, in litres and centimetres.
Enter your tank's size once and get its volume, a stocking guide, substrate and water-change amounts.
Tank volume
Measure the outside of the glass. Width is front to back.
Enter the three sides, or the volume, to see the result.
How many fish?
A rough upper limit for small, slim community fish such as tetras and rasboras.
Enter your tank's size above.
Numbers alone don't tell you which fish live well together. Plan my tank suggests fish that suit your tank and each other.
Substrate
How much gravel, sand or soil for an even layer. Uses the length and width above.
3–4 cm for a simple layer; 5–7 cm for rooted plants.
Enter the tank's length and width above, and a depth.
Water change
How much water to take out.
20–30 % a week suits most tanks.
Enter your tank's size above.
These are general guides, rounded for everyday use. The right filter, heater and light depend on the whole tank — fish, plants, room and budget — so we work those out with you rather than by formula.
Planning a new tank?
Tell us the size, the style and the fish you like, and get a full plan — then ask the studio for a quotation.
Plan my tank