Assassin Snail Care Guide (Clea helena): The Snail That Eats Pest Snails
The Assassin Snail (Clea helena) is a striking gold-and-brown striped snail with a useful talent: it hunts and eats nuisance pest snails. If bladder, pond, or ramshorn snails have taken over your tank, assassin snails offer a natural, chemical-free way to bring the population back under control. This guide covers how to keep them and how to use them.
Quick care overview
- Adult size: about 1 inch (2.5 cm)
- Minimum tank size: 10 gallons
- Temperature: 70–80°F
- pH: 6.5–7.5 (harder water supports shell health)
- Temperament: peaceful toward fish and shrimp adults
- Diet: carnivore (eats other snails and protein)
- Lifespan: about 2–3 years
How they control pest snails
Assassin snails burrow in the substrate and ambush smaller snails, feeding on them one at a time. They are most effective as a slow, steady solution rather than an overnight fix. For a stubborn outbreak, combine them with the manual and preventive steps in our guide on how to get rid of pest snails. Once the pest population drops, supplement their diet so they stay well fed.
Tank setup
A soft, sandy or fine-gravel substrate is important because assassin snails like to burrow. Provide a well-cycled, stable tank with hiding spots and plants. They are peaceful and coexist well with community fish and adult shrimp—live plants also help keep water clean, so browse live aquarium plants for their setup.
Diet and feeding
Assassin snails are carnivores. They readily eat pest snails, but once those run low you should feed them protein-rich foods like sinking pellets, bloodworms, and other meaty foods. They generally ignore live plants, which makes them safe for planted tanks.
Compatibility and cautions
They are safe with fish and full-grown shrimp, but they may prey on very tiny shrimplets, so keep that in mind in a dedicated shrimp-breeding tank. Unlike many aquarium snails, assassin snails have separate sexes and breed slowly, so they rarely become a nuisance themselves. To understand the difference between helpful and pest snails, see our pest snail guide.
Is the assassin snail right for you?
If you want an attractive, low-maintenance way to manage a pest snail problem without harsh chemicals, assassin snails are an excellent choice. Add a few and let them do the work. Find them in our freshwater snails collection.