Assassin Snail - Anentome Helena

Assassin Snail | The Natural Solution to Pest Snail Infestations

The Assassin Snail (Anentome helena) is one of the most useful and fascinating invertebrates in the freshwater aquarium hobby — and one of the few animals that can genuinely solve a pest snail problem without the need for chemicals or manual removal. With its distinctive yellow and dark brown banded shell, sleek conical shape, and surprisingly active, predatory behaviour, the Assassin Snail is as visually appealing as it is practical. Once you have a pest snail problem, these are the first thing you reach for.

Originally from Southeast Asia, Assassin Snails are found in slow-moving rivers, lakes, and streams where they hunt down other snails and worms with remarkable efficiency. In the aquarium, they get straight to work — methodically tracking down and consuming pest species such as Bladder Snails, Ramshorn Snails, and Malaysian Trumpet Snails, bringing even severe infestations under control over time.

Assassin Snail Care Guide

Care at a Glance

• Scientific name: Anentome helena
• Also known as: Bumblebee Snail, Assassin Snail
• Adult size: 1–1.25 inches (2.5–3 cm)
• Minimum tank size: 10 gallons
• Temperature: 75–82°F (24–28°C)
• pH: 7.0–8.0 — prefers neutral to slightly alkaline water
• Hardness: 8–15 dGH — calcium-rich water supports healthy shell growth
• Lifespan: 2–3 years with good care

Assassin Snail Tank Setup

A well-established aquarium with a soft, sandy substrate is ideal for Assassin Snails — they are burrowers by nature and will partially bury themselves in the substrate while waiting to ambush prey. They are most active at night and in low light conditions, though well-fed, comfortable individuals will venture out during the day. Provide hiding spots such as driftwood, rocks, and caves to help them feel secure.

A tight-fitting lid is recommended as Assassin Snails are capable climbers and may attempt to escape, particularly in newly set up tanks or when food is scarce.

Feeding Your Assassin Snails

Primarily carnivorous predators. In a tank with an active pest snail population, they will largely feed themselves — hunting, killing, and consuming other snails methodically and efficiently. Once the pest snail population is under control, supplement their diet with sinking meaty foods such as bloodworm, brine shrimp, and high quality carnivore pellets to keep them in good condition. They will also consume uneaten fish food and detritus.

Will Assassin Snails Eat My Other Snails?

Yes — Assassin Snails will prey on any snail species they can overpower, including Mystery Snails, Nerites, and Trumpet Snails if food is scarce. If you keep decorative snail species alongside Assassins, ensure they are well fed with alternative food sources to reduce predatory behaviour. Larger snail species such as Mystery Snails are generally at lower risk, but no snail is completely safe in a tank with hungry Assassins.

Will Assassin Snails Overpopulate My Tank?

Unlike pest snail species, Assassin Snails reproduce slowly and are unlikely to overpopulate. They lay single eggs attached to hard surfaces, and juveniles take several months to reach maturity. Population growth is gradual and self-regulating — as prey becomes scarce, breeding slows naturally.

Assassin Snail Tank Mates

• All community fish including tetras, rasboras, danios, corydoras, and livebearers
• Shrimp — generally safe, though very small shrimp fry may be at risk
• Avoid pufferfish and other known snail predators
• Use caution when housing with decorative snail species — see above