Assassin Snail: Complete and Detailed Care Guide 2024

Macro shot of assassin snail in aquarium. Anentome helena.
Macro shot of assassin snail in aquarium. Anentome helena.
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: June 9, 2024
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The assassin snail is an exceptional addition to a freshwater aquarium because of its unique appearance, effective tank-cleaning abilities, and its natural tendency to hunt other snails, which sets it apart.

I used to have dozens of unwanted pest snails in my freshwater aquarium until I added a group of assassin snails. Within a couple of weeks, all of the bladder snails were gone, and my tank has never looked better.

If you’re thinking of adding an assassin snail to your tank to control the population of other snails or simply because you like the appearance of them, read on! I’ll be going over everything you need to know about assassin snail care.

Article Summary

  • Assassin snails, also known as bumblebee snails, are freshwater snails native to Southeast Asia, particularly Indonesia, Malaysia, and Thailand.
  • Assassin snails are carnivorous and feed on other snail species, including bladder snails, trap door snails, ramshorn snails, Malaysian trumpet snails, and mystery snails.
  • They are not harmful to live plants and algae, making them suitable for planted aquariums.

Assassin Snail Overview

Assassin snails are a great pet to own if you need help reducing nuisance snail explosions or simply want a vibrant and unique critter to add to your aquarium. Below is an overview of the assassin snail so you can get a good idea of their care needs.

Scientific nameClea helena, Anentome helena
Common namesAssassin snail, bumblebee snail
DistributionSoutheast Asia
Size0.8-1.25 inches
ColorBrown and yellow stripes
TemperamentPeaceful (towards fish)
Minimum tank size10 gallons
Place in tankBottom
Care levelEasy
BreedingEgg layer
Life expectancy2 years

What Is an Assassin Snail?

Like their name suggests, an assassin snail is a snail that eats other freshwater snails, including bladder snails, trap door snails, ramshorn snails, Malaysian trumpet snails, and mystery snails. They are completely aquatic, which means they cannot survive for very long on land.


Assassin snails originate from Southeast Asia in Malaysia, Thailand, and Indonesia. Their natural habitat includes freshwater rivers, lakes, reservoirs, and streams.

They are an invasive species in Singapore and Cambodia due to their predatory nature towards other snails.

Why Are They Called Assassin Snails?

Assassin snails are called assassin snails because they feed on other snails. They can easily take down smaller snails, but a group of bumblebee snails can work together to kill a larger snail.

How Does an Assassin Snail Kill?

Assassin Snail Creeping on a Tank Decoration
(1) Assassin Snail Creeping on a Tank Decoration

The assassin nail has a mouth and a rasping radula (tongue) which they can use to penetrate the shells of other snails. The radula works similar to a scouring pad – it slowly scrapes away at the flesh and blood of their prey while it is still alive.

This process weakens the other snail and eventually kills it.

How Quickly Do Assassin Snails Kill?

Assassin snails usually take around 30 minutes to kill another snail as they slowly rasp away at the flesh of their prey until it is so weak that it cannot survive.

Will Assassin Snails Kill All Snails?

Yes, assassin snails will kill all the snails in your tank, even snails with an operculum, especially if you keep them in groups of over 5. Most specimens eat between 1 to 3 snails every one to three days. A large group of bumblebee snails can work very quickly to eradicate all pest snails in your aquarium.

these critters can attack in groups to bring down larger snails

In addition, these critters can attack in groups to bring down larger snails like apple snails.

Can Assassin Snails Kill Fish?

Assassin snails do not kill fish, but they may finish off fish that are dying or extremely weak. Bumblebee snails are scavengers, so they will feed on fish eggs, dead fish, and decomposing snails or shrimp.

What Are Assassin Snails Good For?

The assassin snail is good for reducing the population of pest snails as well as cleaning up the aquarium by consuming leftover food and decomposing aquatic life. While they will eat all small snail species, they tend to prefer eating trumpet snails, ramshorn snails, and Pest snails.

What Does an Assassin Snail Look Like?

The assassin snail looks like a regular land snail, but they have a siphon that extends out of their shell that enables them to breathe underwater. They have a cone-shaped shell, similar to Malaysian trumpet snails and rabbit snails.

Macro shot of assassin snail in aquarium
Macro Shot of an Assassin Snail in an Aquarium

Assassin snails have yellow/gold shells with dark brown bands, though some specimens are brown with yellow stripes. The assassin snail can also be entirely brown, but this is rare.

How Big Does an Assassin Snail Get?

A mature assassin snail can reach between 0.8 to 1.25 inches. Some specimens can grow as big as 3 inches if they are extremely well-fed, but this is quite rare.

Assassin Snail Gender

Unlike most species of snails, assassin snails are not hermaphroditic and have defined sexes. However, it is impossible to tell the difference between male and female assassin snails.

Tank Size

Bumblebee snails need at least a 10-gallon tank, though larger tanks are always better, especially when keeping assassin snails in large group. It’s best to go for 1 to 2 snails per 5 gallons of water. So, one or two snails should be kept in at least a 10-gallon fish tank.

Fish Tank Being Filled with Water
Fish Tank Being Filled with Water

If you want to keep a few assassin snails, I’d suggest at least a 20-gallon tank. Despite their small size, snails produce a hefty amount of waste!

Water Parameters

The best water parameters for assassin snails are:

  • pH: 7.0-8.0
  • Water temperature: 70–80°F
  • Water hardness: 8-15 dGH

How to Acclimate Assassin Snails

Before you add your new assassin snails to your tank, you’ll need to acclimate them to your water parameters to prevent shock. You should float your new assasin snails in the bag they arrived in your aquarium for around 15 minutes.

Some aquarists drop their snails into their tank after this, but I personally like to drip acclimate mine. This involves adding small amounts of tank water to the bag for around 30 to 60 minutes until at least 50% of the bag water is from your main aquarium. Make sure the display tank water in the plastic bag matches the new tank water parameters as closely as possible.

Suitable Tank Mates

Despite being predatory towards other snails, assassin snails are completely passive towards fish. You can house them with most other peaceful fish species with similar water requirements.

Corydoras Catfish
Corydoras Catfish

Some of my favorite tank mates for these critters are neon tetras, silvertip tetras, harlequin rasboras, cory cats, guppies, platies, and clown plecos.


Bear in mind that assassin snails can eat small shrimp, so they should only be housed with large shrimp species.

How Many Assassin Snails Should I Get?

The number of assassin snails you should own depends on the size of your aquarium and whether you want them to breed. A single assassin snail can live quite happily, but if you want to raise babies, you should get a small group of at least 6.

In addition, if you have unwanted freshwater snails in your aquarium, the more assassin snails you own, the quicker they will eliminate them all.


Assassin snails have a carnivorous nature, so they will not eat live plants. You can safely keep them in a planted tank with all freshwater aquarium plants, but some of my personal favorites include Amazon sword plants, java moss, java fern, anubias, and marimo moss balls.


Take care when keeping assassin snails in tanks that are treated with plant fertilizers containing copper. Snails are sensitive to copper, so make sure you only use brands that are certified for snail safety.

What Does an Assassin Snail Eat?

You can feed assassin snails other aquarium snails like Malaysian trumpet snails, ramshorn snails, nerite snails, and pond snails. They will also eat dead fish, small shrimp, fry, fish eggs, and leftover food in your aquarium.

Assassin snails eat other snail eggs, but usually only those with a soft texture – they tend to dislike hard nerite snail eggs.

Fish Food
Fish Food

If you don’t have other freshwater snails in your tank or a high snail population, make sure you feed them other protein-rich supplements like fish flakes/sinking pellets, brine shrimp, blood worms, and blackworms.

A hungry assassin snail may also attack large snails…

Although they will eat all snail species, these critters prefer eating Malaysian trumpet snails, pond snails, and ramshorn snails. A hungry assassin snail may also attack large snails like apple snails, which can grow up to 6 inches tall!

Here is a video showing an assassin snail hunting and eating other snails.

Assassin Snail Hunting down, Killing, Eating another snail

How Much to Feed Assassin Snails

In fish tanks with a lot of aquarium inhabitants and edible snails, you won’t need to feed your assassin snails that often as they will get most of their food simply by scavenging. However, in smaller tanks with less food sources, you should feed your bumblebee snails once a day.

Offer them a variety of meaty foods like fish flakes, brine shrimp, blood worms, and blackworms.


If you notice lots of empty snail shells in your aquarium, your assassin snails are likely eating very well.

When to Feed Assassin Snails

It’s best to feed assassin snails in the evening when the aquarium lights are off as this is when the species is most active.

How Many Snails Can an Assassin Snail Eat?

An assassin snail can eat between 1 to 3 snails daily or every other day.

Assassin Snail Lifespan

Unfortunately, assassin snails don’t have an overly long life expectancy – most assassin snails live for around 2 years.

However, with great care, healthy and stable parameters, plenty of food, and a large tank size, you can help promote good health in your snails.

Common Diseases

Some of the most common health problems that can affect bumblebee snails are parasitic infections, stunted growth, and brittle snail shells.

Parasitic Infections

Parasitic infections in assassin snails cause white spots to appear on the shell, as well as lethargy and shell damage. Unfortunately, most medications that are used to treat parasitic infections in aquariums contain copper, which is toxic to snails.


It’s best to use herbal treatments for live snails as they are generally safe for invertebrates.

Stunted Growth

Snails that are housed in smaller tanks or are not fed a well-balanced diet are prone to stunted growth. The best way to treat and prevent this is to keep your assassin snail in a large tank and feed them a high-protein diet.

Brittle Shell

Assassin snails can develop weak or brittle snails in unclean water, a lack of calcium in the water, or general assassin snail care issues. You can treat this by increasing the amount of calcium in your water and keeping on top of water changes.

How to Tell If an Assassin Snail Is Dead

An Assassin Snail at the Bottom of the Tank
(2) An Assassin Snail at the Bottom of the Tank

Assassin snails can sometimes look dead as they are slow-moving and can be inactive for fairly long periods. However, there are a few ways you can tell if your snail has passed away.

Examine Its Behavior

First, check the location and position of your snail. If your snail is stuck to a plant or the aquarium glass, it’s most likely alive. However, if it’s laid upside down on the substrate, it has most likely died.

Check the Opening of the Shell

Next, inspect the opening on your snail’s shell. If the shell is empty or the body of the snail is hanging limp from the shell, it’s almost definitely dead.

In addition, the trap door on a healthy snail is always closed for protection. However, in dead snails, the trapdoor is open.

Smell Inside the Shell

The last surefire way to tell if your snail has died is to sniff inside its shell. Aquarium snails decompose very quickly once they die, so you will be able to detect a very foul odor emitting from inside their shell.

Alternatively, lift your snail out of the water – a healthy snail will immediately retract its foot, whereas a dead one will simply lie limp.

Can You Breed Assassin Snails?

Yes, you can breed assassin snails. They are very easy to breed as they will normally mate without any intervention. However, bumblebee snails breed very slowly, so it might take some time before you get any baby assassin snails.

How to Breed Assassin Snails

A Group of Assassin Snail in an Aquarium
A Group of Assassin Snail in an Aquarium

As long as you keep assassin snails in large groups, they will happily breed on their own. However, there are a few things you can do to increase your chances of success.

  1. Keep assassin snails in groups of at least 6 to ensure there is a good mix of males and females.
  2. Slowly increase the water temperature by a few degrees and make sure your snails have plenty of protein-rich food to eat.
  3. If there are other snail species or fish in the tank, move your bumblebee snails to a separate breeding aquarium. Many fish and invertebrates will feed on snail eggs!
  4. Add a fine substrate like aquarium sand to the tank and provide rocks, driftwood, and hard decor so the female has somewhere to lay her eggs.
  5. During mating, the male and female will lock together for up to 12 hours.
  6. Once mating is complete, the female snail will lay her eggs on hard surfaces in the aquarium. It might be best to remove adults as they are prone to eating snail eggs, even their own.
  7. The eggs will hatch into baby assassin snails in between 3 to 8 weeks.

What Do Assassin Snail Eggs Look Like?

Assassin snail eggs are yellow, translucent, and square in shape. They are only around 1 to 1.5 millimeters in size.

The natural prey of bumblebee snails is other small snails, so they are one of the best solutions for controlling pest snail populations. In addition, they are peaceful scavengers, so they make ideal tank mates for passive fish species.

As they are carnivorous snails, they will not eat live plants and algae in your aquarium, so you can safely keep them in planted aquariums.

Bumblebee snails are readily available and should be easy to find online or at your local pet store.


An Assassin Snail found in aquatic pet stores measures approximately 3/4 inches.

Final Thoughts

I hope I helped you learn more about the assassin snail and their care needs. Despite being simple to care for, you’ll need to make sure you provide them with a decent-sized tank, the correct water parameters, and feed them a high-protein diet.

Did you decide to add a bumblebee snail to your setup? Be sure to let me know on our social media platforms, and share this post with your friends and family so they can learn a new thing or two about assassin snail care.

(1) RSX, CC BY-SA 3.0, via Wikimedia Commons
(2) Neptuno33, CC BY-SA 3.0, via Wikimedia Commons

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