Assassin snail (Anentome helena) care guide

Group

Snails

Other names

Bumblebee snail, Clea helena, Clea (Anentome) helena, Snail-eating snail

Family

Nassariidae

Origin

South-East Asia, especially Malaysia and Thailand, and Lake Toba on Sumatra

Water

freshwater

Maximum size

3.2 cm

Temperature

22–28°C

pH

7–8

Hardness

6–15 dGH, 3–8 dKH

Care level

beginner

Care

The assassin snail is a freshwater member of the mostly marine Nassariidae. Its conical shell usually has bold dark brown and yellow-tan bands, though some are all brown. It grows to about 1.8–3.2 cm depending on food, and is often smaller in aquariums. It is kept to control pest snails. Set-up: any established tank with a sand or fine gravel bed, as it spends much of its time buried. The water figures are general guidance rather than from a source: tropical, neutral to alkaline, moderately hard water. It is least active around midday and comes out quickly when food is added. Role and pest control: it is a predator that ambushes snails, often larger than itself, and worms. One or a few will gradually clear bladder, ramshorn and Malaysian trumpet snails. Once pest snails are gone it will eat leftover meaty food. It does not breed fast, so its numbers stay modest. Invasive risk: where released it can seriously threaten native freshwater snails. Never release this animal or empty its tank water into drains or waterways. Copper: copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most other invertebrates. Never dose them in a tank holding this animal, and read the label of any treatment, fertiliser or algae remover before use. Sources: Wikipedia (en.wikipedia.org/wiki/Anentomehelena). Checked October 2026.

Diet

A carnivore. It eats other snails and worms, sucking the snail out of its shell. When pest snails run out, feed sinking meaty foods such as bloodworm, brine shrimp, shrimp pellets or fish pellets.

Breeding

Sexes are separate but males and females look the same, so keep five or more to get a pair. Mating pairs lock together for hours. The female lays single clear, square egg capsules about 1–1.5 mm across, each holding one yellow egg, on rock, wood, plants or glass. The young hatch after a few weeks as tiny snails and bury themselves in the substrate for months before appearing. Breeding is slow, which keeps numbers in check.

Compatibility and tank mates

Safe with fish and plants. It will eat other snails, including small nerites, mystery snails and ornamental ramshorns, so keep it away from snails you want to keep. Adult shrimp are normally safe, though it may eat dead or weak ones and possibly shrimplets. Loaches and puffers may eat it.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.