Assassin Snail
Assassin Snail

Assassin Snail

Clea helena
SynonymsAnentome helena
DistributionIndonesia, Malaysia, and Thailand.
Sexual DimorphismNo obvious external differences. Non-hermaphroditic.
Maximum Size2cm (0.8”)
Water ParametersModerately hard, alkaline water is best. pH: 7.2-8.0, dH 10-25 deg.
Temperature22-27 deg C (72-81 deg F)
LightingNo special requirements

The carnivorous Assassin Snail is a small, freshwater whelk species suited to tropical aquaria. In the wild, it feeds on carrion, worms and other gastropods. This is quite an active snail that will roam in its search for food. When at rest, it usually buries itself into the sandy substrate with just its sensitive proboscis (or ‘snorkel’) protruding; if food items are detected moving past, the snail quickly stirs into action. In the aquarium, the Assassin Snail will feed on ‘pest’ snails such as pond snails and Malaysian trumpet/livebearing snails, which can sometimes reach plague proportions if not kept in check. They themselves will reproduce in the home aquarium, but not usually at such as alarming rate. Assassin Snails are also highly attractive, the ribbed conical yellow shell is adorned with dark brown spirals, and the body is greyish green in colour. Although this is a relatively hardy snail, it naturally requires good water quality (preferably with decent current) and a soft sand substrate in which to burrow. Larger ornamental snails are usually safe from Assassin Snails, but they will prey on small juveniles of such species. There are occasional reports of Assassin Snails attacking small shrimp, but in well fed specimens, this is not the norm. Aquatic plants are perfectly safe from these opportunistic carnivores. May also be seen on sale as the Snail-Eating Snail.


Offer a variety of meaty foods. Will consume small snails, bloodworm, white mosquito larvae, vitamin-enriched brineshrimp & Mysis, sinking catfish pellets/granules etc.


Assassin Snails will reproduce in the home aquarium, but at a relatively slow rate compared to that of many ‘pest’ snails. As they are non hermaphroditic, a large group should help to ensure you have both sexes. After mating, which can take several hours, eggs are laid singly in tiny semi-transparent pouches that are affixed to the glass and décor. Once hatched, the young tend to disappear beneath the substrate, and are only seen several weeks – even months – later.

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