Assassin Snail (Anentome Helena): Care guide in the Aquarium

Assassin snails are a popular freshwater creature that many people want to own. Their clean patterns and low maintenance nature make them the perfect addition to many tanks!

They are also great for getting rid of any snail pests that may be invading your tank. Simply drop some assassin snails into your aquarium and your problem is solved.

Because we are such fans of this species, we wanted to put together a dedicated care guide. They deserve it!

In this guide you will learn everything there is to know about assassin snail care. Diet, tank conditions, reproduction and more. It’s all here.

Species Summary

The assassin snail (Clea helena or Anentome helena) is a unique addition to freshwater tanks. While most other snail species are used exclusively to keep ecosystems clean, these creatures have a different claim to fame. They are carnivores that like to feed on other snails!

As such, they are often introduced to tanks that are overrun by pest snails. Even a small collection of assassin snails can take over a large colony of smaller species in a few weeks.

Originally found throughout Southeast Asia, assassin snails have become very popular with aquarists. Not only do they serve a practical purpose in fish tanks, they are also very easy to care for.

Life expectancy

The average lifespan of the assassin snail is between 2-3 years.While that is the norm, some enthusiasts have reported these gastropods living for more than 5 years!

Tank conditions and diet play a large role in their overall health and lifespan. These snails have a unique diet that must be adhered to. Otherwise, they may not even make it to the 2-year mark.


Whether you plan on using an assassin snail to control the snail population or not, they sure are a joy to watch. Unlike other snails that have a soft shell, this species has some color. The shells have brown and yellow stripes. This has led to the nickname «bumblebee snail».

Some snails have a solid brown shell, but it is quite rare compared to the striped pattern.

The shell itself also has some unique properties. It is conical and has a blunt point at one end.

When the snail feels threatened, it retreats into its shell to protect itself. The interesting thing about this behavior is that the snail is fully capable of keeping itself safe from most small predators. That’s because it has an operculum. Basically, it is a trapdoor that allows the snail to enclose itself in its shell.

To move around the tank, the killer snail has a very muscular foot. Contracts to help the creature navigate its environment. Of course, the snail’s movements are slow and steady. You can often find the snail clinging to glass or climbing rocks.

The body of the snail acquires a light beige shade. It is covered in brown and black specks, which no doubt help the snail blend in with the substrate.

On its head, you will see two short tentacles. The eyes are located at the ends to help the snail detect light and movement.


In captivity, the average size of an assassin snail is about an inch long.Some can grow up to 2 inches long on the right diet, but that’s pretty uncommon.

Author’s Note: Despite their small size, these critters tend to have quite a presence in your tank. Its neat appearance more than makes up for its diminutive nature!

Killer Snail Care

For the most part, assassin snails are very easy to care for. They are very low maintenance and can thrive without much fuss.

Priority requirements are good tank conditions and plenty of nutritious food. Failing to provide this significantly increases the chance of illness and a shorter lifespan. Here are some of the most crucial care tips that you need to follow.

tank size

Realistically, you don’t need a huge tank to give Assassin Snails a full life. Due to their small size, they will do well in a moderate sized tank with plenty of places to explore.

At a minimum, they should be kept in a 10-gallon tank.It is recommended that you add 5 gallons to that size requirement for every two snails you keep.

In general, of course, a bigger tank is always better. Many Assassin Snail owners prefer to put these gastropods in tanks up to 30 gallons in size so they feel like they are in open space and have no need to try to escape.

Author’s Note: If you are a homeowner who is committed to maximizing the lifespan of your assassin snails, we recommend getting a tank that exceeds the minimum recommended size. These creatures thrive when they have space.

water parameters

In the wild, assassin snails can be found in tropical climates. They live in slow-moving rivers filled with soft sand and lots of rocks. Rivers in Southeast Asia tend to be somewhat alkaline, so snails do best in water conditions that mimic this quality.

Temperatures should be on the warmer side. Any significant change to a cooler temperature range can lead to shell problems and death.

  • Water temperature: 70 to 80 degrees Fahrenheit (aim for medium)
  • pH levels: 6.5 to 7.5
  • Water hardness: 2 – 15 dKH

What to put in your tank

The good news is that you don’t have to do much to please Assassin Snails! Gastropods spend most of their time at the bottom of rivers when they are free. They will do the same in captivity.

It is important to know that these snails like to dig and hide. Because of this, the substrate must be loose enough to allow them to slowly cover.

This means that you will want to have a substrate of fine sand at the bottom of your tank.This is soft and easy for them to bury. Using a large or thick substrate can damage their tentacles and skin.

For the most part, a sandy substrate is the only high-priority requirement for assassin snails. You can feel free to decorate the rest of your tank however you like.

We like to go the extra mile when it comes to our creatures, and we think you should too. Including some rocks and climbable driftwood is something we highly recommend as it gives these snails places to explore.

Plants are also welcome. In general, having plants with snails is a bit risky. They are prone to eating and destroying them. However, that is not the case with Assassin Snails.

This is because these snails are carnivorous. They don’t really care one way or the other if you have plants!

When it comes to equipment, there are also no strict requirements. The movement caused by normal filters is more than enough current for these snails. You don’t need a fast moving bomb or air stones.

However, you should pay close attention to the effectiveness of your filtration. Assassin snails need high quality water to thrive. Invest in a good filter (like the FX4) to make sure organic matter doesn’t make your water too dirty. Still, you should replace a good portion of water each week.

Author’s Note: Since these little critters love to climb, you should make sure your tank is covered. Filters should also be equipped with sponges to prevent accidents and leaks.

Possible common diseases

Don’t make the mistake of thinking that snails can’t get sick. They are fully capable of disease like fish.

One of the most common problems these snails have to deal with is parasitic infections. They usually appear as white spots on the shell. Unfortunately, treating these infections is easier said than done.

Many different types of parasites could infect assassin snails. Furthermore, most treatments used to cure fish are lethal to gastropods. For example, copper-based drugs can kill these snails quickly.

If you notice any signs of disease, your best bet is to separate the snails from any fish that may become infected. You don’t want your snail problem to affect the entire tank!

As always, prevention is the best way to manage disease.If you provide great care and have impeccable water quality in your tank, the chance of your assassin snail getting sick is significantly reduced.

Food and Diet

Assassin snails are carnivorous and only eat protein-based foods.Their favorite type of food is actually other snails that are smaller than them.

They are also not demanding. These animals will attack any snail they can. Many owners feed them trumpet snails, rabbit snails, ivory snails, and ramshorn snails. Assassin snails also feed on the eggs of other snail species.

If those aren’t available, fried shrimp and bloodworms work well. You may also find your snail eating brine shrimp or leftover flakes that fall to the bottom of the tank.

One good thing about Assassin Snail care is that you don’t need to worry about overfeeding. Assassin snails like to pace themselves and have a fair amount of self-control (unlike many fish).

This means that you could realistically provide a good feeding snail population and let the killer snail eat slowly over time!

behavior and temperament

Assassin snails are pretty solitary creatures. They are more active at night and like to keep to themselves. If you don’t see the snail attached to the glass, it is most likely hiding in the sand.

This is a normal behavior that snails practice in the wild. They hide in the sand and wait for an unsuspecting snail to pass by.

Aside from their carnivorous nature, these snails are not aggressive at all and usually don’t even recognize other creatures. This is pretty normal when it comes to snails, and this species is no different.

tank mates

Assassin snails are not aggressive to fish (not surprisingly). The only thing you need to worry about is pairing them up with tankmates who will see them as food!

Snails do best with community fish that occupy the upper parts of the tank. Bottom dwellers can also work. However, they must be gentle scavengers who do not eat the snails.

Here are some of our favorite Assassin Snail tank mates for you to consider:

  • neon tetras
  • corydora catfish
  • guppies
  • cherry picks
  • Angelfish
  • gourami pearl
  • heavenly danio

Assassin Snail Breeding

Assassin snails have no problem reproducing in captivity. In fact, they can multiply quickly if you have a lot of them in a tank!

Unlike other gastropods, these snails are not hermaphrodites. Defined sexes exist, but it is virtually impossible to tell them apart by appearance alone.

You can keep a collection of 6 or more snails in a tank to increase the chances of successful breeding.

The snails have a little mating ritual. The bugs pair up and follow each other for several hours. This is a noticeable change in behavior as most snails don’t even recognize each other under normal circumstances.

Once the assassin snails have mated, the female will lay eggs on whatever firm surface she can find. The tiny eggs take about a month to hatch. At that point, the babies will burrow into the sand until they are a bit older and ready to emerge.

The adults don’t usually eat the young, so you don’t need to worry about separating them.


Assassin snails are a fantastic freshwater creature to include in your tank, plain and simple.

They are easy to care for, look great and will eliminate any snail pests that may appear in your aquarium. Basically, you get a ton of benefits and zero drawbacks.

We highly recommend you pick a few for yourself, but if you’re still undecided, feel free to let us know! We love to talk about these animals and enjoy listening to our readers.

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