The short answer
The best pest-snail eaters are assassin snails and certain snail-eating loaches — yoyo loaches and dwarf chain loaches especially. An assassin snail hunts and eats bladder, pond and ramshorn snails one by one, while loaches crunch through them in a bigger tank. But remember the underlying cause: pest snails boom from overfeeding, so predators work best alongside cutting back the food that fuels the outbreak.
Assassin snails — the invert-friendly option
The assassin snail is the go-to for most tanks. It’s a small, attractive snail that actively hunts other snails, and a group of three to five will steadily clear an outbreak. Best of all it’s safe with fish and mostly safe with shrimp — it targets snails, not swimmers. In a peaceful community or shrimp-friendly tank, assassins are the cleanest solution.
Snail-eating loaches
For a larger, fish-only tank, loaches are voracious snail hunters. Yoyo loaches and dwarf chain loaches are the classics, seeking snails out of the substrate and decor. The catch: loaches are active, need a group and a bigger tank, and most will also eat shrimp — so they’re not for a shrimp setup. Some pufferfish eat snails too but have their own demanding care needs.
The method that actually works
Predators are only half the answer. Cut feeding so the snails lose their food supply (how often should I feed my fish), remove snails by hand, and let a predator mop up the rest — the full routine is in how do I get rid of pest snails. For why the boom happens at all, see will my snails take over my tank, and choose cleaner-feeding foods on our fish food hub.