Clea helena, commonly known as the assassin snail, is a small freshwater snail native to Southeast Asia. It features a striking yellow shell with dark brown spiral bands, and is carnivorous, preying on other snails and detritus in its aquatic habitat.

Clea helena, commonly known as the assassin snail, is native to Southeast Asia, particularly found in regions of Thailand, Indonesia, and Malaysia.

Clea helena inhabits freshwater environments such as rivers, ponds, and lakes. These areas typically have sandy or muddy substrates, and the water conditions range from slightly acidic to neutral with moderate hardness.

The assassin snail is a carnivorous species that plays a role in controlling populations of other freshwater snails, which can be considered pests in aquariums. It is adapted to life on the substrate where it hunts for its prey, often hiding under sand or debris during the day and becoming more active at night.