This free aquarium snail stocking calculator tells you how many cleanup snails your tank needs, from its litres and algae level, without overloading the tank. It runs fully in your browser, so nothing you type is sent to a server, and you need no account and no sign-up to use it.
Aquarium problems usually build slowly. A tank that looks fine today can drift over weeks when feeding, stocking, or water changes stay unmeasured. Small numbers, checked early, stop most trouble before fish show stress. This tool turns a guess into a number you can act on, and that number is easier to trust than a rough rule of thumb from a shop assistant.
To use the tool, type in Tank size (litres), Algae level. Press the calculate button and the tool shows the result at once. If you change any number, press calculate again to see the new result right away. Try a few values to see how sensitive the result is to each input.
Example: a 100 litre tank with moderate algae suits about 10 cleanup snails, well under the safe maximum of 20 for that size.
Fix the cause of algae, not just the symptom. Snails eat algae, but algae grows from excess light and nutrients, so cut light hours and check feeding first.
Do not overfeed to feed snails. Uneaten fish food feeds snails fast, and a snail population explosion usually means the tank is overfed, not under-cleaned.
Check snail shells for cracks and white patches. Soft or pitted shells mean soft water or low calcium, so add a calcium source and check hardness before shells fail.
Common question: Will snails take over my tank? Some species breed fast, so choose species and numbers with care. Mystery and nerite snails breed far slower in freshwater than bladder and ramshorn snails.
Common question: Do snails clean glass well? Yes for soft green algae and biofilm, but not for hard green spot algae or thick brush algae. For those, a scraper and less light work better.
Common question: Are snails safe with plants? Most cleanup snails eat dead leaves and algae, not healthy plants. If snails eat live plants, they are usually starving, so feed blanched vegetables as a supplement.
Keep a short notebook by the tank. Write the date, the numbers you entered, the result, and anything you changed afterwards. That short record turns a vague feeling that something changed into clear evidence. After a month you can look back and see which choices helped and which ones did not, and that makes the next decision much easier.
The most common mistake is changing too much at once. When several things change in the same week, you cannot tell which change caused the result you see. Change one thing, wait, watch the fish and the water, and only then change the next thing. Slow, single changes keep a tank stable, and stable tanks keep fish healthy.
Recheck the numbers whenever anything changes in the tank. New fish, a new filter, a different food, or a change in room temperature can all shift the right answer. A quick recheck takes less than a minute and stops an old number from quietly becoming wrong. Bookmark this page so the recheck is easy.
This tool is free to use as often as you like. Bookmark it, recheck the numbers when your tank changes, and keep the daily routine steady. Small, steady habits matter far more for an aquarium than any single perfect number, and a calm routine is what fish respond to best. If a number surprises you, run the tool twice with different inputs before you act on it, and trust the steadier result.