Assassin Snail
Clea helena
Edited by Ivan F. · Reviewed
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
- Can live alone
- Lifespan
- Not well documented
Assassin Snail tank mates
Danio rerio
Puntius titteya
Barbodes semifasciolatus
Poecilia reticulata
Poecilia wingei
Xiphophorus maculatus
Paracheirodon innesi
Their pH ranges barely overlap, so you will have little room for error.
Paracheirodon axelrodi
Their pH ranges barely overlap, so you will have little room for error.
Hyphessobrycon herbertaxelrodi
Their pH ranges barely overlap, so you will have little room for error.
Hemigrammus erythrozonus
Their pH ranges barely overlap, so you will have little room for error.
Hyphessobrycon amandae
Their pH ranges do not overlap, so one of them would always be stressed.
Boraras brigittae
Their pH ranges do not overlap, so one of them would always be stressed.
Corydoras paleatus
Their pH ranges do not overlap, so one of them would always be stressed.
Ancistrus cirrhosus
Their pH ranges do not overlap, so one of them would always be stressed.
Common tank-mate questions
Assassin Snail feeding and care
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 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 setup
The essentials for a small, gently filtered tank.
TankAt least 5 US gal (19 L)
The smallest tank our sources give for Assassin Snail. We list only tanks that hold this volume (allowing 10%, so a standard size counts).
Picks for Spain are still being checked. The options below are for the US, and we have not confirmed that they are sold in Spain.
Aqueon Standard Glass Aquarium 10 Gallon US
Tetra Complete LED Aquarium Kit 10 Gallon US
Why we chose these (Best 10-Gallon Fish Tank: What to Look For). Nobody here has used or tested them.
Starter kitA kit with the tank, filter and light in one box
We list only kits whose tank fits Assassin Snail, up to twice its minimum volume. A kit whose heater has a fixed setting shows only when that setting is inside Assassin Snail's temperature range.
Tetra Crescent Kit 5 US
No heater included
Tetra Complete LED Aquarium Kit 10 Gallon US
No heater included
Tetra Starter Line LED Aquarium 30 L Spain
No heater included
Why we chose these (Best Aquarium Starter Kit: What to Look For). Nobody here has used or tested them.
FilterAir-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
Fluval AquaClear 20 Power Filter US
Tetra Brillant Filter Spain
Fluval AquaClear 20 Power Filter Spain
Why we chose these (Best Filter for a 10-Gallon Tank). Nobody here has used or tested them.
HeaterKeep it at 70–80 °F (21–27 °C)
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
Aqueon Pro Adjustable Heater 50 W US
Fluval T50 Fully Electronic Aquarium Heater Spain
Eheim Thermocontrol e 50 Heater Spain
Why we chose these (Best Heater for a 10-Gallon Aquarium). Nobody here has used or tested them.
Water conditionerDechlorinator such as Seachem Prime
Tap water contains chlorine or chloramine that harms fish.
Seachem Prime US
Fritz Complete Water Conditioner US
API Betta Water Conditioner US
sera aquatan Spain
Tetra AquaSafe Spain
Sold at Kiwoko · Sold at Tiendanimal · Sold at zooplus.es · Maker's details
Why we chose these (Best Water Conditioner for Betta Fish). Nobody here has used or tested them.
Test kitLiquid kit such as API Freshwater Master
Tracks ammonia, nitrite, nitrate and pH while the tank cycles.
API Freshwater Master Test Kit US
API General & Carbonate Hardness Test Kit US
See it at The Shrimp Farm (a retailer; affiliate link) · Sold at Bulk Reef Supply · Maker's details
sera aqua-test box (Cl) Spain
JBL PROAQUATEST COMBISET Plus NH4 Spain
Why we chose these (Best Test Kit for a Freshwater Aquarium). Nobody here has used or tested them.
SubstrateDoes well on gravel too; it naturally lives buried in a soft substrate.
We are still choosing products for this.
PlantsSafe with live plants
Browse all aquarium plants.
Cycle the tank before adding animals. See our guide on how to cycle a fish tank.
Where to buy Assassin Snail
Stores that list it under the same scientific name as this page. Links marked as affiliate links may earn us a commission. We have not bought from them, so check each store's own terms.
See it at The Shrimp Farm (a retailer; affiliate link)
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 local rules below)
Some US states restrict certain species. Check our US state aquarium rules table and your state's own rules before you buy.
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 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.
Assassin Snail facts and sources
- Type
- Snail
- Native to
- Southeast Asia
- Adult size
- 1 in (2.5 cm)
- Temperament
- Semi-Aggressive
- Diet
- Carnivore
- Live plants
- Yes - Loves Plants
- Breeds in freshwater
- Yes
Sources
- Aquarium Co-Op: Care and water figures
- The Shrimp Farm: Supporting figures
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