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Photo: RSX, CC BY-SA 3.0

Assassin Snail

Clea helena

Edited by Ivan F. · Reviewed November 8, 2026

EasyFigures from specialist keeper sources

Beginner verdict

A striped predatory snail that hunts other snails, making it a natural fix for a snail outbreak. It is safe with fish and most plants, and it breeds slowly, so it rarely becomes a problem itself. It will also hunt the snails you want, so choose its tank carefully.

Care at a glance

Min tank size: 5 US gal
Temperature: 70–80 °F
pH: 7.2–8
Hardness: No figure published
Swim zone: Bottom
Min group: Single fish
Lifespan: Not well documented

Check your local rules on Assassin Snail

Official lists name this animal or its close relatives. Rules differ by place, so check the rules where you live before you buy or keep one.

Georgia
Georgia's wild animal rules require a wild animal license for Anentome helena, the name MolluscaBase now accepts for this snail.
Source: Rules of the Georgia Department of Natural Resources, rule 391-4-8-.05 (Secretary of State)

Never release aquarium animals or plants into the wild, including into ponds, rivers or drains.

This is general information, not legal advice. We last checked these lists on 4 November 2026, and the US state lists on 8 November 2026. Our US state aquarium rules table shows every state, including the ones whose lists we could not read. We did not check Spanish regional rules, and other countries have their own.

Assassin Snail care mistakes to avoid

Keep it away from snails you value, including nerites and mystery snails.
Watch dwarf shrimp, especially babies, because the risk is debated among keepers.
Provide sand if you can, as it likes to burrow.
Avoid puffers and snail-eating loaches, which will eat it.

Assassin Snail tank mates

Zebra Danio
Danio rerio
Cherry Barb
Puntius titteya
Gold Barb
Barbodes semifasciolatus
Fancy Guppy
Poecilia reticulata
Endler's Livebearer
Poecilia wingei
Platy
Xiphophorus maculatus

Common tank-mate questions

Can Bettas Live With Snails?

How to feed

Let it hunt pest snails, which are its main food.
Offer bloodworm or sinking pellets when snails run out.
Add mineral-rich food, because its shell needs calcium.

Assassin Snail FAQ

What size tank do Assassin Snails need?

Our sourced minimum is 5 US gallons (19 liters). A bigger, mature tank is always easier to keep stable.

What can live with Assassin Snails?

Good matches on our list include Zebra Danio, Cherry Barb and Gold Barb. Avoid Ember Tetra and Chili Rasbora.

How long do Assassin Snails live?

Lifespan is not well documented for this species. Stable water and a good diet help any animal live longer.

Will assassin snails wipe out all my snails?

Over time they can greatly reduce pest snails, but rarely all of them. Remove any snails you want to keep before adding them.

Where to buy Assassin Snail

Stores that list it under the same scientific name as this page. We earn nothing from these links. We have not bought from them, so check each store's own terms.

Shop in:

Sold at The Shrimp Farm

We have not found a store that sells Assassin Snail under its scientific name yet. We add stores as we confirm them.

Live animals and plants travel by courier. Check the store's live-arrival guarantee, and only buy once your tank has cycled (see how to cycle a fish tank).

Not allowed without a permit in: Georgia (see the note above)

Some US states restrict certain species. Check our US state aquarium rules table and your state's own rules before you buy.

Complete the tank

The essentials for a small, gently filtered tank.

Shop in:

Tank size for this species
At least 5 US gallons (19 L)
Filter
Air-driven sponge filter
Gentle flow that small fish and long fins can handle, plus a safe home for good bacteria.
- Aquarium Co-Op Coarse Sponge Filter (Small) US
  Check the voltage: this filter runs from an air pump, which plugs in. Mains power is about 120 V in the US and about 230 V in Spain, so choose a pump sold for your own country.
  Maker's page
- Fluval AquaClear 20 Power Filter US
  Check the voltage: this model is listed for the US. Mains power is about 120 V in the US and about 230 V in Spain, so do not assume it suits another country.
  Maker's page
- Tetra Brillant Filter Spain
  Check the voltage: this filter runs from an air pump, which plugs in. Mains power is about 120 V in the US and about 230 V in Spain, so choose a pump sold for your own country.
  Maker's page
- Fluval AquaClear 20 Power Filter Spain
  Check the voltage: this model is listed for Spain. Mains power is about 120 V in the US and about 230 V in Spain, so do not assume it suits another country.
  Maker's page · Sold at Kiwoko · Sold at Tiendanimal
Why we chose these (Best Filter for a 10-Gallon Tank). Nobody here has used or tested them.
Heater
Adjustable heater, about 5 W per gallon: 25 W at 5 gallons, 50 W at 10
Keeps a small tank stable. Adjustable models let you set the temperature your species needs. Size up for a cold room.
- Fluval T50 Fully Electronic Aquarium Heater US
  Check the voltage: this model is listed for the US. Mains power is about 120 V in the US and about 230 V in Spain, so do not assume it suits another country.
  Maker's page
- Aqueon Pro Adjustable Heater 50 W US
  Check the voltage: this model is listed for the US. Mains power is about 120 V in the US and about 230 V in Spain, so do not assume it suits another country.
  Maker's page
- Fluval T50 Fully Electronic Aquarium Heater Spain
  Check the voltage: this model is listed for Spain. Mains power is about 120 V in the US and about 230 V in Spain, so do not assume it suits another country.
  Maker's page · Sold at zooplus.es
- Eheim Thermocontrol e 50 Heater Spain
  Check the voltage: this model is listed for Spain. Mains power is about 120 V in the US and about 230 V in Spain, so do not assume it suits another country.
  Maker's page · Sold at Kiwoko · Sold at Tiendanimal
Why we chose these (Best Heater for a 10-Gallon Aquarium). Nobody here has used or tested them.
Water Conditioner
Dechlorinator such as Seachem Prime
Tap water contains chlorine or chloramine that harms fish.
- Seachem Prime US
  Maker's page · Sold at Bulk Reef Supply
- Fritz Complete Water Conditioner US
  Maker's page
- API Betta Water Conditioner US
  Maker's page
- sera aquatan Spain
  Maker's page · Sold at Kiwoko · Sold at Tiendanimal
- Tetra AquaSafe Spain
  Maker's page · Sold at Kiwoko · Sold at Tiendanimal · Sold at zooplus.es
Why we chose these (Best Water Conditioner for Betta Fish). Nobody here has used or tested them.
Test Kit
Liquid kit such as API Freshwater Master
Tracks ammonia, nitrite, nitrate and pH while the tank cycles.
- API Freshwater Master Test Kit US
  Maker's page · Sold at Bulk Reef Supply
- API General & Carbonate Hardness Test Kit US
  Maker's page · Sold at The Shrimp Farm · Sold at Bulk Reef Supply
- sera aqua-test box (Cl) Spain
  Maker's page
- JBL PROAQUATEST COMBISET Plus NH4 Spain
  Maker's page
Why we chose these (Best Test Kit for a Freshwater Aquarium). Nobody here has used or tested them.

Cycle the tank before adding animals. See our guide on how to cycle a fish tank.