How about a ‘snail’ eating another snail to keep the snail population under control in the fish tank? Sounds confusing, right? Well, it isn’t.

Here we will talk about snail species that are widely used to prey on other pests/snails to eradicate the population explosion in the fish tank. These are none other than- Assassin Snails. Initially found in the freshwater bodies of South-East Asia, in places where they can find soft muddy substrates, these have become quite a suitable option for tank mates in the aquarium.

Known as the aquarium snail killer, they bring in the required diversity. Therefore, apart from seeing your fish pets swimming here and there all day, you get to see a creature slowly moving up and down the plants gracing the whole mini-ecosystem created within.

How do you keep them? What are the ideal living surroundings for them? Do they pose any threat to your plants? Continue reading to clear your doubts.

All about the Species

Quick Species Facts
Scientific Name Anetome Helena
Other Common Names Killer Snail, Snail Killer, Clea Helena, Bumblebee Snail, Carnivore Snail, Bumblebee Assassin Snail
Family Pachychilidae
Origin Cambodia, Malaysia, Laos, Indonesia, Thailand, Vietnam 
Lifespan Up to 2 Years
Size 2 – 2.5 centimeters
Type Freshwater Snail

Summary and Characteristics

Often called the “Killer Snail,” this creature is one of the harmless pets that you keep in your aquarium, completely non-aggressive towards fish and shrimps already residing in. While many aquarists use this as a solution to keep the pests’ explosion under control, it should be noted that it is not a permanent answer.

You must keep your tank free from uneaten or unnecessary food, and vacuuming is one way to do it. Subsequently, petting these won’t be a pain as long as you keep the tank’s condition under check. Stability in water parameters is the sole mantra for keeping these lively and healthy.

One must know that these like to live in groups. So, you must buy at least half a dozen to maintain a balance. Of course, the tank’s size increases with an addition in the number. One striking fact about them is that they do not breathe air as other snails do, making them more prone to illness due to sudden changes in water quality.

Expert Tip: These tiny creatures can carry a parasitic nematode called Angiostrongylus. Humans may get gastrointestinal or central nervous system disorders as a result of this infection. Thus, follow precautions while touching them with bare hands.

Assassin Snail Care- Diet and Breeding
Image Credit: user: Werner73


It does not take an expert to encounter these small snails in a fish tank. The yellowish-brown pattern of this creature gives it a clear indication. These shell shapes can vary from snail to snail, and on most occasions, the very pattern of scales determines the species it belongs to. Its conical yellowish-brown stripes derive the name ‘Bumblebee’ for it.

Starting from the head, you get to see a couple of short tentacles having an eye on the base of each. These parts are the observational organs of this creature and help it to track any movement and light.

Digging in a little deeper, you can find a structure called the Operculum. It is a Trap Door that instantly closes the door whenever the snail is inside. A translucent muscle foot called the Propodium is responsible for movements such as climbing and burrowing.

Under rare circumstances, you might find the soft body of this killer snail to be utterly brown in color.

Quick Fact: Operculum is often observed to notice whether the assassin snail is healthy or not. If the creature is sick, it won’t close properly, and it falls off once the snail dies.

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Max. Size

Though their size is small, you cannot keep your eyes from noticing this slowly moving piece in the aquarium.

If you wonder how big assassin snails can get, it is hard to get them to extend their length up to 1 inch (around 30mm) or more. This is only possible if you have the idealistic conditions set up from day one till the very end of its life. From nutrition to water parameters to tank mates residing in, it can be anything that limits the growth of this creature.

Max. Life Expectancy

As with any other creature living in your fish tank, the life of your snail depends largely on the environment it is living in. While many aquarists believe it is an easy species to take care of, you shouldn’t take it any lighter. As mentioned, it requires a specific diet (plentiful of pest snails) and an environment running according to them.

If you want to get the specifics of how long snails live, here are the numbers. The average life of this creature is close to 2 years. Many professionals have reported their snails living up to the 5-year mark, but this truly is a next-to-impossible thing in a home aquarium.

Gentle Reminder: Since you’d be keeping more than a couple together, you must ensure each of them has an adequate diet rich in pest snails/proteins. Therefore, be specific on the number of snails you introduce in your aquarium.

Gender Identification

The only way to identify the gender of an assassin snail is by looking at them while they are mating. Yes, it is true since their external structures do not hold any difference to distinguish a male from a female.

Author’s Note: Since it is inevitable to get hold of a male or a female killer snail in one go, it is advised that you buy 6 or 7 of them. This enhances your chances of getting a couple together if you are looking to breed.

Assassin Snail Care

Quick Care Facts
Care Level Easy to Moderate
Social Temperament Peaceful
Diet Carnivore
Breeding Intermediate

Diet and Feeding

The diet of an Assassin Snail is strictly restricted to the carnivore segment, and it means your live plants are free from any sort of attack from this species. Speaking of their diet, they are very good at limiting themselves and won’t even have another go if they are full.

Other small snails walking on the substrate or plants are no less than a treat for these predatory snails in the aquarium. They won’t be picky in any term and would feed on every tiny snail coming into their arena. Further, if there is ever a shortage of this platter, feel free to feed them shrimp fry and bloodworms.

On odd occasions, you might find them feeding on meaty flakes sinking to the bottom. If you wish to know the most preferable items that assassin snails like to eat, note- Rabbit Snails, Ivory Snails, Ramshorn, and Trumpet Snails.

Temperament & Social Behavior

Much like any other organism from this family, this snail is slow in movement. You won’t be seeing any of them moving at a pace. They like to come out in the dark. Hence, you can expect to see less of them during day time.

If they are not climbing or moving over the substrate, they are most likely to be hidden in the sand, waiting for another small snail to come above. Any sense of a small creature above leads to an attack.

Besides any of it, you won’t notice any signs of aggression from this peaceful piece. However, if you wish to see them active during the daytime, start feeding them during the day. They’ll most probably develop a habit of it.

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Breeding and Eggs

Breeding these won’t pose any problem to you. Unlike any other organisms living in your water tank, these do not require a very specific surrounding to mate. A stable environment is enough for the breeding process to initiate.

Here comes the critical question, how do assassin snails mate and reproduce?

It is a necessity for both sexes to be present for mating. Since it is hard to tell the gender from a mere look, you should captivate more than half a dozen to enhance the chances of getting both genders in together. The first sign of an assassin snail’s breeding exists when you see one snail following another for several hours.

Further, when the couple gets comfortable, you will see one stuck over the other. And this is when the mating process has been initiated. This can take up to 12 hours. Once they detach themselves, the female will lay an egg on a hard surface. After 3 weeks or so, the assassin snail’s eggs hatch, after which the fry goes deep into the substrate. The baby assassin snail only comes out after 3 or 4 weeks.

Pro Note: This species multiplies up to a great extent. It is a rare sight to see a killer snail feeding on its own fry. The parent does not usually feed on their belongings. Hence, you may not necessarily remove the parent from the tank.

Common Diseases

It won’t take a professional’s eye to notice that a snail is sick. The formation of white spots over the shell is a clear indication. This happens due to parasitic infection. It can be anything, from a plant to any other organism, to depleted water quality that makes it prone to falling sick.

Also, do not commit the mistake of putting this pet on the same medication as that of a fish. It can harm its life even more. Therefore, the best practice would be alienating your snail and protecting the other fishes from catching the infection.

Of course, prevention is one sure shot of keeping your snail’s health on top. Make certain the water conditions are stable and up to the mark.

Pro Tip: Two things should be at your fingertips. The first one is the ‘copper element.’ It should not enter the tank in any form, even through medications. The second is ‘Calcium,’ and it should be present in abundance to ensure the shells are strong from within.

Tank Recommendations

Quick Care Tank
Minimum Size 10 Gallons
Water Temperature 70˚F – 80˚F
Water Hardness 3 – 15 dkH
pH Level 7.1 – 7.3

Ideal Tank Size

Though this pet is small in size, it still needs some room to have an exciting life. You cannot expect your assassin snail to live in a 3-gallon pot. Eventually, it will try to escape. Hence, the minimum size recommended is 10 gallons.

Whenever you add a couple more, you need to add 5 gallons to the size of your tank. The space, of course, shrinks with toys, plants, and other creatures swimming above. Hence, you should at least have 10 gallons ready for a pack of 5 to 6.

Tank Setup, Décor, and Plants

For all we know, these creatures allow you to try every bit of creativity in decorating the tank. There is only one limitation- The Substrate. Snails like to burrow, and you will find them hiding inside the sand. Therefore, make sure it is soft for an assassin snail to dig (even fry).

Several critters like to destroy your live plants, but assassins are quite the opposite. They are solely restricted to their carnivore diet and won’t eat plants. Further, the lighting can be as bright as you wish. Bright LED light allows proper exposure to plants, and you will find your pet climbing over a life.

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With a steady current, some driftwood, a small toy, and plenty of space to enjoy, this Killer Snail will definitely pose a ‘Killer Look.’

Pro Tip: Since they climb up and may even reach the top of the tank, you should keep the lid closed. This reduces the chances of escape.

Water Parameters

First things first, the assassin snail’s care is not as minor as their size. You have to be very careful of the water quality you are availing to your pets. These like to have steady water conditions. Hence, stick to the recommended pH level, hardness, and temperature for as long as you can.

Water temperature is crucial to the life of an assassin snail. Coldwater is no less than an enemy for these. Any shift from a warm environment to the cold will lead to problems such as shell breakage and even death. Investing in a good quality filter is indeed a necessity. Plus, a weekly water change is also recommended.

If you are thinking about nitrate level, you should keep it below 20 ppm. Having freshwater surrounding all their life, assassin snails will thrive elegantly if your tank mimics their originality. Talking of the numbers, note these- Temperature: 80˚F, pH: 7, and hardness: 8dKh

Compatible Tankmates

We all know that these like to mind their own business. Owning their peaceful character, they won’t pose any problem to any of the tank mates, including fish and other assassins. The only thing you should check is if the other organism treats this as its meal or not.

For most occasions, your betta won’t try to eat it as it swims on the top level. Subsequently, peaceful community fish won’t be getting on its nerves as well. Here is a list of compatible tank mates for your pet:

Avoid bottom-dwelling fish such as pufferfish, crayfish, plecostomus, and cichlids at all costs.

Frequently Asked Questions

Do Assassin Snails eat shrimps?

Yes, assassin snails will try to prey on shrimps smaller in size than them. However, it is a rare site since shrimps move fast and rarely fall in the clutches of this slow critter. The only time they get hold of one is if the shrimp is ill or dead.

How much do they cost?

The cost of this creature varies from place to place. It ranges from $3 to $9 in some areas. It largely depends on the age and size of your pet. A fry usually costs less. However, you should make sure you are buying a healthy pet. Monitoring their movement is one way to know it.

Do Assassin Snails Harm Plants?

Unlike many snail species that like to hinder your plant’s look, killer snails do not practice the same. With them, the chances of your plants remaining as gracious as they were are close to 100%.

Are assassin snails poisonous?

Their mechanism of poisoning their prey by injecting makes them poisonous creatures. These snails paralyze their prey with the help of their venom, thus, liquefying the flesh for complete swallow.

Will Assassin Snails eat each other?

The sight of one killer snail harming the other is rare. That is why these are bought in groups of 6 or 7. This is generally because they do not pose any threat to one another, just to other pests or small snails.

What to feed Assassin Snails?

Being carnivores in nature, these like to stick to other small organisms in the aquarium. You won’t be seeing them disturbing any plant. Though there are chances, they may feed on flakes at the bottom. A list of preferable food is mentioned above.

Do Assassin Snails eat Trumpet Snails?

Yes, they like to have trumpet snails served. They are very fond of this food item. The menu of an assassin snail can be diversified with ramshorn snail and pond snail. For the record, they will eat 1 to 3 snails a day.

Do assassin snails eat Algae?

No, you won’t be seeing your pet feeding on algae. They only and only crave carnivore food and won’t be eating any other snack.

Final Remarks: Are They Good for your Aquarium?

When it comes to petting these, it is a no-brainer. They diversify your tank like no other and do not pose any threat to any organism residing in it. When we talk about its care, it is on the easier side as well. If you are wondering how many assassin snails should I get? We recommend starting with half a dozen (Do not forget to look at the minimum tank size).

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About the Author

Shelby Crosby

Shelby is a passionate fishkeeper who has been writing about fish for over 5 years. She is a pro aquarist and holds a BSc Honors Degree in Wildlife and Fisheries. She creates her own beautiful aquarium layouts and loves to share her knowledge of tropical fish with other hobbyists. Career Highlights: Has worked with several…

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