What this tool does

This interactive aquarium stocking calculator works out how many fish you can safely keep in your tank based on your specific setup. It considers your tank size, filtration capacity, and the biological load of different tropical fish species to prevent overcrowding and water quality problems.

The tool also flags potential problems like aggressive species combinations, warns you about overstocking risks, and tells you what maintenance schedule you will need to keep your fish healthy.

When to use it

Use this tool when planning a new tropical fish tank, adding new species to an existing setup, or if you are concerned your current tank might be overstocked. It is particularly useful if you are considering mixing different species and want to check they will get along without causing stress or territorial disputes.

The calculator is also helpful when upgrading your filtration system, as it shows you how improved water processing might allow for additional fish in your tank.

How it works

You enter your tank volume, setup type, and filter specifications, then select the fish species you want to keep and how many of each. The tool calculates the total bioload, checks for species compatibility, and compares this against your tank's capacity to process waste safely.

It then gives you specific recommendations for safe stocking numbers, maintenance requirements, and any special care needs for your chosen species. The tool accounts for adult fish sizes and territorial behaviour, not just the small juveniles you might buy from the shop. Nothing you enter is saved, and you do not need to create an account to use it.