Assassin Snail – Complete Care Guide

Looking for a way to get rid of pest snails? If so, an Assassin Snail may be an option for you. You’ll want to read this complete care guide that goes over these unique inverts. I’ll cover their diet, tank requirements, breeding, and more. So if you are interested in learning more about these snails, keep on reading!

Scientific NameAnentome helena/Clea helena
Common NamesAssassin snail, Bumblebee snail, Snail eating snail
FamilyNassariidae
OriginSoutheast Asia
DietCarnivore
Care LevelEasy
ActivityModerate
Lifespan2-3 years
TemperamentAggressive to other snails and shrimp
Tank LevelBottom level and substrate
Minimum Tank Size30 gallons
Temperature Range70 to 80° F
Water Hardness2-15 KH
pH Range6.5 – 7.5
Filtration/Water FlowSlow to fast
Water TypeFreshwater
BreedingEgg layer
Difficulty to BreedEasy
CompatibilityCommunity tanks
OK, for Planted Tanks?Yes

Origin and Habitat

The assassin snail originates from Southeast Asia, including Vietnam, Thailand, Sumatra, and Malaysia. There, they live in freshwater rivers, streams, and lakes. They prefer a muddy substrate where they can easily burrow and wait to emerge for prey. Sometimes they will keep their proboscis exposed to stay alert about nearby food.

Assassin snails are very resilient and will adapt to most water conditions. This has led them to become the most predominant snail in some ecosystems as well as to become an invasive species in other countries. If left unmonitored, this can start to affect local snail populations.


Introduction to Assassin Snails

Got a snail problem? Assassin snails might just be the answer.

Assassin snails are unlike any other freshwater snail available for purchase in the aquarium trade. Though gruesomely named, the assassin snail is actually a perfect, peaceful candidate for the planted community aquarium.

As with most planted aquariums, live plants bring in unwanted pest snails that quickly reproduce and overpopulate the system. While some hobbyists use manual removal or chemical intervention to keep populations down, others turn to a natural predator: the assassin snail.

These small snails stay about an inch big at full size but have a big appetite for other snails and other meaty foods!

How Long Do Assassin Snails Live?

Assassin snails don’t live for a long time like other snails. On average, they live to be about 2-3 years. As we’ll see though, these snails are surprisingly very easy to breed, making for exponential replacement when the time comes.

Are Assassin Snails Good For Your Freshwater Tank?

Assassin snails are good for some freshwater tanks. They are pure carnivores that feed mostly on smaller snails and uneaten food. Unlike other freshwater snails, they will not clean algae or plant detritus though they will take care of a pest snail infestation in exchange. This means that if you don’t have a snail problem, the assassin snail is most likely not for you.

How Assassin Snails Kill

But how do these apex predators of the snail world kill? We’ll be honest, this isn’t for the faint of heart but the method used undoubtedly earns these snails their killer name.

How Do Assassin Snails Kill?

The assassin snail isn’t poisonous or venomous. Instead, they have a deadly tongue-like structure called a radula.

In most other aquarium snails, the radula is lined with tiny teeth that scrape away algae from hard surfaces and are harmless to other snails. In the assassin snail, the radula is designed to extend into the shell of other snails, scraping away and eating the mucus and flesh of the other snail while it’s still alive.

During this process, different fluids and smells enter the water column, attracting other assassin snails and leading to a frenzy. In no time, the only thing left of the victims is empty snail shells alongside a group of full assassins.

In most cases, assassin snails will only eat snails that are smaller than them or about the same size. This leaves larger snails, like nerites and mystery snails, largely unscathed; however, there is the chance that your assassin snails gang up on a larger snail and ambush prey them. Still, they prefer eating trumpet snails, ramshorn snails, and pond snails.

It should be noted that assassin snails have been known to eat freshwater shrimp as well as shrimp fry. While more uncommon to see, they will eat the dwarf shrimp from the inside out in the same style.

Can Assassin Snails Kill Fish?

Of course, many new assassin snail owners question whether or not these snails are safe to keep with their fish. The answer is yes! Assassin snails are regularly kept with all types of tropical fish in a community setting, including bottom feeders.

If you happen to find an assassin snail eating a fish, it’s very likely that the fish was already dead. Remember, assassin snails are very efficient scavengers that feed on meaty foods other than pest snails. They will gladly take the opportunity to eat a dead fish.

There is also the chance that your assassin snail will eat fish eggs as well as other snail eggs.

Can Assassin Snails Sting You?

No, the assassin snail does not have a stinger and is not venomous. You are completely safe to work in and around your tank without having to worry about upsetting or getting injured by your assassin snail.

More than likely, this myth came about due to their somewhat similar appearance to the unrelated cone snail (Conus spp.) that is extremely venomous. No worries, though! There is no chance of an aquarium store confusing an assassin snail for a cone snail.

How Many Snails Do Assassin Snails Kill?

On average, one assassin snail eats one to three snails every one to three days. Of course, this will depend on a few factors including food availability and the size and appetite of the individual snail.

The biggest concern with this is that once the snails disappear, the food also disappears. At this point, other foods will need to be supplemented.

Do Assassin Snails Kill Each Other?

Interestingly, assassin snails do not kill each other. It is not known what allows an assassin snail to recognize its own species, but they will firstly starve to death before turning to cannibalism.

How To Identify An Assassin Snail

Though more uncommon to happen, assassin snails can unknowingly come in on live plants and other aquarium decorations.

If you have decorative snails that you want to keep, then you’ll definitely want to know how to identify an assassin snail before they start eating your prized snails; to help prevent any pest snails from entering the aquarium at all, it’s always recommended to dip-treat live plants and quarantine.

The problem is that assassin snails stay small for a very long time and stay buried in the substrate. Once they’ve grown, they are very easy to identify, though.

Assassin snails grow to be about an inch big at mature size. Some of the larger individuals reach closer to 2 inches. They have alternating vertical black and yellow stripes along the sides of their shell.

They are most identifiable by the shape of their conical shell that ends in a sharp whorl. Along the sides of the shell are noticeable ridges that lead to their small foot. Two antennae and a proboscis will stick out from under the shell. The proboscis is the nose of the snail which helps to locate food.

Assassin Snail Care

Keeping assassin snails is easy though keeping them fed can be difficult once the number of pest snails available starts to decline.

Tank Size

There is some discussion about the minimum tank size required for assassin snails. These are small snails that don’t create a lot of waste, but their diet and heavy preference for live foods make their recommended tank size bigger than expected.

In general, a 30 gallon tank is recommended to keep assassin snails. About one to three snails are recommended for a tank this size. More or less should be added based on the number of pest snails present.

If you are adding assassin snails for decoration only and planning to regularly supplement meaty foods, then hobbyists have had success keeping assassin snails in as little as 5 gallons. In these cases, waste management needs to be monitored as uneaten meaty foods can quickly affect water quality.

Aquarium Setup

For the most part, assassin snails stay buried in the substrate. They will greatly prefer a sandy, silty bottom as opposed to gravel. Otherwise, there are no special aquarium setup requirements for keeping these snails.

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Assassin snails can gladly be kept in a planted aquarium. They are strictly carnivores and will not eat live plants. Since they don’t require algae to eat, providing surface area for algae to grow does not matter as much as it does for other species; always keep in mind the needs of your other tank mates, though!

Water Parameters

Assassin snails are very hardy and can adapt to most water parameters. They need 0 ppm ammonia, 0 ppm nitrite, and minimal nitrates. They are intolerant to traces of copper.

However, assassin snails are somewhat more sensitive to incorrect water temperatures than other snails. They do best at a constant water temperature between 70-80° F. Though they originate from tropical climates, they prefer relatively cooler temperatures–though, not as cold as some snails can endure, like pond snails.

Filtration and Aeration

Many freshwater snail species like to graze on the algae and detritus collected by sponge filters. Assassin snails do not benefit from this additional filtration.

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Instead, they will happily live with whatever kind of filtration you choose to give them, including sponge, hang on the back, canister, and sump filtration. Some hobbyists even keep them in unfiltered tanks that rely solely on beneficial bacteria and live plants.

Additional aeration is also not needed. This may change due to the other species being kept in the tank and the overall bioload.

Lighting

Assassin snails can be kept in low, moderate, and high lighting. Again, lighting will depend more on the other fish, invertebrates, and plants being kept in the aquarium.

That being said, assassin snails spend the majority of their time in the substrate. If the lighting does bother them, they will have no problem correcting the situation by hiding more.

Aquatic Plants and Decorations

Assassin snails don’t care if you have plants or not, but their food might. As carnivores, assassin snails will not touch plants. However, many other species of snail, like Malaysian trumpet snails and ramshorn snails, love to feed on the algae that grow on leaves and stems.

To help create a natural habitat for these freshwater snails to grow and to supply your assassin snail with food, it’s strongly recommended to keep live plants.

Community Tank Mates

Assassin snails can be kept in a tropical community fish tank. However, they should not be kept with wanted snails or shrimp.

Compatible tank mates include:

These snails are not bothered by fish, including bottom-dwellers, though avoid snail-eating fish species as assassin snails are easily preyed upon. There is some discussion as to whether or not they can eat small fish, but it’s likely they only target fish that are already dying.

How Many Assassin Snails Should Be Kept Together?

It can be difficult to gauge how many assassin snails your aquarium needs. They eat about one to three snails every one to three days, so the total number should be considered in regard to food availability.

In general, about one to two snails are recommended per every 10 gallons.

Can You Keep Just One Assassin Snail?

Yes! You can keep just one assassin snail. These snails aren’t particularly social and don’t need others to feel safe. In most cases, it’s best to keep only one assassin snail so that feedings stay easy.

Assassin Snail Food and Diet

Feeding assassin snails isn’t as difficult as it sounds.

First and foremost, these snails will appreciate pest snails as the staple of their diet. If you find that your snails are eating more than your snails can reproduce, then it may be worthwhile to cultivate those snails in a separate aquarium. This doesn’t need to be anything elaborate. A 5 gallon aquarium with some fast-growing plants can be the breeding grounds for many species of freshwater snails.

If you don’t have the space to set up another tank, then you will need other options. Believe it or not, assassin snails will accept fish flakes and pellets. A protein-rich food should help supplement your snail’s diet, but other live and frozen foods should also be offered regularly.

These snails will appreciate a variety of live and frozen brine shrimp, mysis shrimp, and bloodworms. Feedings should be at least two to three times a week.

Breeding Assassin Snails

For a long time, it was believed that assassin snails reproduce slowly. While they may lay only one egg at a time, they are efficient reproducers (video source).

Breeding assassin snails is straightforward. They are likely to breed on their own without any hobbyist intervention if a male and female are present in the tank. To begin breeding, gradually raise the water temperature over the course of a few days. Provide a rich diet.

If successful, the female will lay fertilized eggs. These eggs can be moved to breeding tanks to ensure that nothing eats them, though this is usually unnecessary. Assassin snail eggs are about 1 millimeter in size and translucent yellow or white. The eggs should hatch in about one to two months.

Many hobbyists think they are unsuccessful when they see the egg missing with no baby assassin snails in sight. Babies are very small and likely to hide in and around the substrate for the first several months, so it’s not uncommon to not see them for a while.

If you want to stop breeding assassin snails, simply squash the eggs as you see them appear.

Do Assassin Snails Reproduce Asexually?

Unlike other freshwater snails, assassin snails do not breed asexually; a male and female need to be present. They are also not hermaphrodites, meaning that they stay one sex for the entirety of their lives.

There are no observable differences between males and females, so breeding will need to happen in a group setting where there’s a good chance of having both sexes present.

Final Thoughts

If you’re struggling with a snail infestation, then an assassin snail or two will help keep populations in check. These snails are very undemanding and can adapt to most aquarium conditions. They especially love spending time in the substrate but will emerge to hunt for other snails as well as to help clean up dead fish and other meaty wastes.

Just make sure that you can supplement your snail with foods after the pest snails have run out!

by Mark

Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping - both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.

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