How to Get Rid of Pest Snails (and the Good Snails Worth Keeping)

Snails appearing from nowhere? Here is how to control a pest snail outbreak - and why some snails are actually your aquarium's best friends.

Where pest snails come from

Tiny bladder, pond and ramshorn snails usually arrive as eggs hidden on new plants. They are harmless and even useful - they eat algae, leftover food and waste - but they multiply fast when there is excess food, so a sudden population explosion is really a sign you are overfeeding.

How to control them

The simplest, most effective fix is to feed less - cut the food and the population naturally shrinks. You can also remove them by hand, or set a simple trap: place a blanched vegetable or a sinking wafer in the tank at night and lift out the snails that gather on it in the morning. Repeat for a few nights to make a real dent.

Natural snail predators

Assassin snails hunt and eat pest snails and are a popular, peaceful control. Some loaches (like yoyo and zebra loaches) and pufferfish also eat snails enthusiastically. Add these only if they suit your tank, and remember assassin snails will also eat snails you want to keep.

The good snails to keep

Don't tar all snails with the same brush. Nerite snails are the best algae-eaters and can't breed in freshwater, so they never overrun a tank. Mystery snails are large, colourful and peaceful. Both are genuine assets - see our snail and invertebrate guides in the database. Avoid chemical snail killers, which can harm shrimp, some fish and your filter.

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