Assassin Snail Stats InfographicAssassin snail, scientifically known as Anetome Helena, is a freshwater species of snails that you can find throughout Southeast Asia. They might not be the first choice for most fish owners because of the difficult care level. But they are quite interesting to raise.

If you want them to be a part of your fish family too, we have done all the necessary research for you. This article will give you important information about them, starting from care, diet, and tank size to breeding, and reproduction.

Why Are They Called Assassin Snails?

They are especially prominent in countries like Malaysia, Thailand, and Lake Toba of the Indonesian island named Sumatra. Because of the bee-like patterns on their shell, they are also called Bumblebee Snails. But they are mainly called the “assassin snail” for their habit of eating other snails.

That’s right, it might be hard to picture a snail-eating snail, but that’s how they work. Assassin snails feed on smaller snails and larger ones by burying themselves in the substrate and then ambushing their prey. That’s why they can be a serious threat to native freshwater gastropods when introduced in a country.

However, this trait of theirs also helps keep the populations of some freshwater snails in check. This is because most of these snails breed explosively. The most common example is a trumpet snail. If you own trumpet snails, they might end up laying an extremely large amount of eggs when overfed. So keeping a few assassin snails in the tank can reduce the number of trumpet snails to a moderate one.

Assassin Snail Stats

Care level Intermediate
Maximum Size 3″ to 4*
Minimum Tank Size 30 gallons
Average lifespan 2 years
Diet Omnivore
pH 6.5 to 7.5
Hardness 2 to 15 dKH
Temperature 70F to 80F
Temperament Peaceful
Order Neogastropoda
Family Nassariidae
Genus Anentome
Species Anentome helena

Assassin Snail Appearance

Assassin snail dietAssassin snails have a unique appearance than most other snails because of their shell. The conical-shaped shell usually consists of dark brown and yellowish-tan bands, which is what gave them the name bumblebee snail. However, there are some specimens that do not have this kind of banding and instead have a completely brown shell.

Assassin Snail Coloration

Their body is of a light color, with darker flecks here and there and a very thin but prominent proboscis. It looks a lot like the proboscis of a trumpet snail. But it is much thinner in comparison as well as lighter in color.

Assassin Snail Care

It is moderately difficult to care for a freshwater assassin snail. So this is a job you should take if you consider yourself at least an intermediate level when it comes to being a fish owner. For a beginner, some of the things that these snails are notorious for doing might be a bit challenging. But it’s not impossible as long as you do the proper research and avoid making common mistakes. However, prior experience and knowledge will help you out a lot.


This is a species that naturally occurs in Southeast Asia, so you can imagine that they will need a tropical temperature inside the tank. They do not like frequent shifts in the water temperature parameters. So make sure that the aquarium’s temperature remains well-heated, and the water is properly filtered. It’s always a good idea to monitor the parameters on a regular basis to make sure the snail doesn’t acquire stress from the frequent change.

Medicine in Case of Disease

If you have other fish in the tank and one of them catches a disease, you might need to apply medication to the water. Medicine for fish usually has copper in them. But assassin snails are very sensitive to copper, and it might not only harm them but also prove to be fatal for them. Some kinds of plant fertilizers might also be the same. So before you apply these to the water, make sure to double-check whether the additive is safe for the snail.

Assassin Snail Diet

Assassin snails are carnivorous, which is to say they are scavengers and predators. You cannot feed them algae and such types of foods. Live organisms are the best for them to prey on. If they are snails or different types of worms doesn’t matter; if they are not strong enough to escape or fight back from the clutches of an assassin snail, they will become assassin snail food. Dead organisms and other meaty leftovers can also be fed to them.

An interesting thing you will notice about assassin snails is the fact that they have super-sharp senses. They can always sense when food has been added to the tank regardless of the distance. As they are predatory mollusks, they use this sense to sense potential food nearby. They will usually remain hidden in the substrate and stay as still as possible.

But the moment you put food in the tank and they sense it, they will emerge and begin to crawl actively throughout the tank. You will notice that their proboscis remains fully extended during this. Once they locate the food source, you might see them attack in groups. They won’t fight each other, but they will show a competitive behavior on who can get the food first.

Assassin Snail Lifespan

The lifespan of assassin snails is very short. They can live up to two years at most if they are healthy. If the water conditions and diet are perfect, some hobbyists have also said that their assassin snail has lived up to four or even five years. But it is quite rare.

Assassin Snail Size

As you might already know, most fish don’t grow too much when they are held in captivity inside a home aquarium compared to when they are in their natural habitat. For assassin snails as well, it’s not an exception. Typically the assassin snail size for juveniles is around one inch, depending on the food sources. But the adult ones you find in stores can be around three to four inches long.

Keep them under the right water conditions. Feed them well, keeping enough live food and meaty food in their diet. Then they will grow healthy, and you can expect to see them be upwards of three inches. So make sure the tank is big enough and has the capacity to hold multiple adult assassin snails.

Assassin Snail Tank

Assassin snail care guideAssassin snails do not grow too big, so many people simply put a bunch of them in 10-gallon tanks. While that is totally enough for them, the issue mainly lies in the water parameters. As we mentioned before, assassin snails are sensitive to changes in the parameters. It is almost impossible to always monitor the sudden changes and keep them constant, and it might even become annoying for you at some point.

Why are Large Tanks Preferable?

The shift in the parameters is more evident in a smaller tank than it is in a larger one. A larger tank with more water will absorb the shift well and neutralize it all across the area. So the overall shift becomes negligible. That is why we recommend getting a minimum tank size of 30 gallons for your assassin snails. You don’t have anything to lose in getting bigger tanks!

Another reason why smaller tanks are no good is that you will have to keep other snails in the tank for your assassin snail to feed on. A sufficient amount of them has to be kept in the tank at all times so that it might get a bit cramped in there. You also have to keep their growth rate in mind. The more an assassin snail grows, the more snails they need to be fed.

So you can calculate the number of snails the assassin snail can eat and choose the number accordingly. This will also help you get an understanding of what tank size might be sufficient. You will most likely keep like five to six assassin snails together as well, so you will need even more snails for all of them. In this case, do a rough calculation and get a bigger tank according to it. Smaller tanks are better kept out of the question.

Assassin Snail Tank Requirements

You need to work on many things before you introduce your assassin snails to the tank that’s going to be their new home.

  • First, make sure that the tank is fully cycled and established itself.
  • Check the stability of the parameters.
  • Keep the Ammonia and Nitrite levels at 0ppm as more of it is harmful to them.
  • Even when you’re doing regular partial water changes, try to keep the Nitrite level as low as possible.

Assassin Snail Tank Mates

The best tank mate for your assassin snail can be any species of fish that enjoys snails as a part of its diet. On the other hand, any fish that will not bother snails and leave them alone is also fairly compatible with assassin snails. You can keep a variety of fish in the same tank as them, and they won’t show any signs of harming them. They usually just don’t care.

Can They Be Kept in the Same Tank As Cherry Shrimps?

A frequently asked question among owners of assassin snails is whether they can be kept in the same tank as red cherry shrimps. Some fish owners have raised cherry shrimps in the same tank without any trouble, and they coexisted just fine. However, some aquarists in different fish forums have claimed that their assassin snails have attacked and eaten red cherry shrimps as well as other small fish.

Worst Assassin Snail Tank Mates

So it’s better to stay on the safe side in such cases. Puffers and loaches of medium to large sizes are the worst kind of choice as a tank mate. Another species that some owners have claimed to be incompatible with is the olive nerites. Here too, there is a difference in opinions like the cherry red shrimp, so it’s safe to assume that it varies from case to case.

Assassin Snail Towards Other Snails

For a snail that eats other snails, it’s not a surprise that assassin snails can attack any type of snail. They typically don’t show any tendencies of cannibalism. But it might surprise you to know that they can attack snails that are bigger than them in size if they get too hungry. You might only expect to see something like that in a parasitic food chain, but it’s rather common for assassin snails.

Assassin Snails vs. Mystery Snails

One example of such a case is the mystery snails which are not immune from assassin snails. However, since they have an operculum, mystery snails can sometimes withstand an onslaught from assassin snails. An operculum is like a protective door that closes the shell tightly when the snail feels threatened. But then again, trumpet snails also have an operculum, but it doesn’t help them in any way.

Types of Snails They View as Snacks

That aside, these predatory gastropods will show the tendency to eliminate most types and species of snails that they find in the same aquarium. Some examples are the ramshorn snail, pond snails, and Malaysian trumpet snails. So if you plan to raise other snails instead of giving them away as food, then placing them in the same tank as assassin snails is not a good idea. However, tiny, almost diminutive kinds of snails might be left alone by the assassin snail.

Assassin Snail Breeding

Assassin snail breedingMany snails are hermaphrodites, owning the reproductive organs of both males and females. These kinds of snails are capable of producing both eggs or young. However, research has found that assassin snails are never hermaphrodites. They are born either male or female and stay that way throughout their lives.

So assassin snail reproduction happens in a normal manner. However, it’s quite difficult to distinguish the male from the female because of how similar in shape and size they are. If you want them to breed at some point, it’s always best to get five to six of them together instead of just two. If you do that, you can hope to obtain individuals of both sexes.

This will help maintain a balance within the tank. A meaty diet will positively impact their reproduction, as it makes them feel more energetic. So keep feeding them different types of meat before the breeding time, which should happen between a week to 10 days after you purchase them.

Assassin Snail Reproduction Process

The First Part: Laying The Eggs

The male and the female lock together for several hours after choosing each other as their partners. The female lays a bunch of clear egg capsules, each containing a single, small yellow-colored egg. These capsules are square in shape and around half an inch in width and height. The female snail usually lays these egg capsules on the solid surfaces of the tank or at the base of plants.

Second Part: Wait For Eggs to Hatch

After being fertilized, the assassin snail eggs should hatch within the next few weeks. So it will be a while before you see any of the juveniles in your tank. Many snails tend to reproduce in an explosive way, making it impossible to control the population inside a tank. But assassin snails have never shown such a tendency. They reproduce in a moderate amount, and their population density is never too high, which is obviously a good thing.

Third Part: They Stop Snail Overpopulation

That is another reason why many people buy assassin snails for their aquarium if they have other snails in there too. Assassin snails keep the population of overly reproducing snails in control, and they themselves don’t reproduce in large amounts. Thus, maintaining the right type of balance. After all, there is no point in reducing the population of one type of snail only to increase the population of another.

Fourth Part: Juvenile Assassin Snails

After a while, you will start to notice a bunch of juveniles in the tank. They might be a little hard to spot, especially if there is an algae overgrowth in the tank, so be very watchful. These juveniles will grow up and then breed again. But their rate of reproduction is nothing like most other snails, so you don’t have to worry too much. If their number becomes large, then you can simply drop some off at a local fish store!


And that is everything you need to know about assassin snails if you are planning to get one of your own. Let’s take a look at all the important points once more:

  • Assassin snail lookAssassin snails are freshwater snails naturally occurring in Southeast Asia.
  • They are notorious for being snails that eat other snails, as they mainly prey and feed on other species of snails of different sizes.
  • Assassin snails can be used to keep the population of other snails under control when they reproduce in large amounts.
  • They are sensitive to frequent changes in water parameters and certain fertilizers and additives.
  • Copper can be fatal for assassin snails.
  • The bigger the tank is, the less frequent the water parameters’ shift will be, so it’s always recommended to buy a larger tank for them.
  • The ideal tank mates for them are fish who eat snails as well as fish who don’t bother snails.
  • It’s best to buy five to six assassin snails at once if you want them to reproduce within few weeks.
  • Make sure to give them a meaty diet so that they can reproduce quickly and create healthy juveniles.

Whether you want to control the snail population in your tank or simply find assassin snails pretty because of their gorgeous shell, these guys can be a great addition to your aquarium. You have to put some extra care into raising them, but it’s definitely worth it because they’ll make your aquarium look so charming.

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