Assassin snail crawling in tank

Assassin Snail Care: Types, Tanks, Diet And More

What is an Assassin Snail?

Assassin Snails is a popular freshwater snail these days. They’re useful tank members because they can help keep other snail populations in check, especially Ramshorn, Trumpet, and pond snails. However, if you’re looking for an algae-eating snail, Assassin snails are not your choice as they’re carnivorous.

Unwanted snails often enter tanks as hitchhikers on live plants. In these situations, Assassin snails can be your friend and help you eliminate your snail problem. Assassin snails are carnivores and will eat the other pest snails as a snack. You could say they really earn their name.

Assassin snails themselves are great tank additions – they have nice patterns and won’t eat your plants. They’re simple to care for and breed but it is still important to be educated when preparing to have Assassin snails in your tank. As long as you know how to care for them properly, you will be set-up for success.

Below, we’re going to discuss everything you need to know about Assasin snails. We’ll review their tank requirements, diet, lifespan, and breeding. Spoiler alert – all of it is pretty easy so enjoy!

Assassin Snail: Overview

The assassin snail (Clea helena) is an aquatic snail that belongs to the Buccinidae family. Not surprisingly, their name originates from their carnivorous diet. They eat other small snails. They’re the assassins in your tank.

In the wild, they’re native to Southeast Asia, especially Malaysia, Thailand, and Indonesia. They’ve become quite popular in home aquariums due to their snail control services. However, this popularity has also helped them spread, with concerns about their ability to become an invasive species quickly.

They lay their eggs in the nooks of plants, which makes it incredibly easy for the species to spread if the aquarium plants move beyond the aquarium.  Because they’re carnivores, their diets would naturally extend to wild snails and invertebrates, which could already be experiencing population issues.

Assassin snails aren’t pricey if you’re looking to add a few to your tank. A single snail will cost around $2, with bulk discounts often extended for more than one.

Assassin Snail: Appearance

Like most aquarium snails, Assassin snails are small. Expect adult snails to reach about 1 inch in length. Wild snails tend to be a little bigger.

Assassin snails have a conical shell with brown and yellow stripes. Some variants lack stripes and are completely brown but these versions are rare. 

The Assassin snail is a snail of many nicknames. In addition to Assassin, it is also called the “bumble bee” snail because of its yellow and brown stripe patterns.

Assassin snail crawling on leaf

Assassin shells have an operculum, which is a door the snail can close to help the snail hide inside. Additionally, the snail has a strong muscle inside the shell, which is contracted to help the snail move. This results in the famously slow pace of the Assassin snail.

Lastly, the head has a pair of short tentacles. These are focused on scanning the tank for food. Additionally, each tentacle has an eye at the end of each tentacle which can detect light and motion – additional surveillance techniques for their assassin work in your tank. 

Assassin Snails have a mouth and radula (similar to a tongue) that they stick into their prey’s shells. The radula basically rubs the prey’s shell thin, to the point where their mouth can eventually reach the flesh of their prey. Gruesome stuff, yes, but important to know as an Assassin snail owner.

Assassin Snail: Lifespan

Assassin Snails live about two years, on average, in captivity. Some hobbyists report their Assassin Snails have lived more than five years but this is rare.

Assassin Snail: Size

Assassin snails are small snail species. Expect adult snails to reach about 1 inch in length when they’re full grown.

Assassin Snail: Care

A good rule of thumb when planning to include any species in your tank is try to mimic their natural environment as closely as possible. 

The Assassin Snail’s natural habitat is freshwater bodies of water in southeast Asia which are tropical and tend to be slow-moving. The water is warm, gets plenty of sunshine, and typically slightly alkaline. The soil at the bottom of the river or lake is soft and sandy. Assassin snails love to bury themselves in soft, sandy soils. Typically there are plants scattered around, with random rocks and pieces of wood which provide plenty of hiding nooks and crannies. 

Make sure your freshwater tank resembles their natural habitat to keep Assassin Snails happy and healthy.

Assassin Snail: Habitat


30 gallon tanks are the minimum recommended size for this species. Assassin Snails thrive in aquariums with stable water parameters, which is easier to maintain in larger tanks. The water conditions do not fluctuate as wildly in large tanks as they do in small tanks. 

Further, Assassin Snails feed on other snails, so the tank must be able to support 2 species of snails simultaneously in order to have sufficient food available.

Additionally, the growth rate of Assassin Snails must be considered. Larger Assassin snails require more food, which means a larger population of consumable snails, which means a larger tank. 

Lastly, Assassin Snails are often kept in small groups of five or so, which further increases the bioload of the tank. Simply put, smaller tanks are not capable of supporting Assassin snails with ideal tank conditions.

Our recommendation: Seaclear 30 gallon aquarium

Water Conditions

Keeping everything consistent is important for your snails’ health. Assassin snails are easy to care for but do require consistent water parameters. 

The tank water needs to be well-filtered and heated. Fast-flowing water isn’t important so your filter will create enough current for them. Don’t worry about lighting; Assassin Snails are not picky about lights.

You want nitrates as close to 0ppm as possible for Assassin Snails. They are slow eaters (they’re snails, of course) which means their food will tend to rot, which can lead to spikes in nitrogen compounds. Regularly testing your water with a freshwater kit is a good idea.

  • Aquarium pH: 7.0 – 8.0. Some hobbyists suggest a wider range is possible.
  • Temperature: 70 – 80 Degrees Fahrenheit.
  • Hardness: Water should be on the hard side for shell health and growth.
  • Lighting: Wide range acceptable.

Assassin Snail: What to put in their tank

Assassin snails like to bury themselves in the substrate. It is part of their hunting strategy; they wait here for small snails above them and pounce (relatively speaking) when they get the opportunity. For this reason, it is advised to use a fine substrate, like sand or soil in your Assassin snail tank. You want it to be fine and soft so it doesn’t damage their body or tentacles. Additionally, their burrowing skills assist with the free flow of oxygen and nutrients to plant roots by breaking up any soil compaction.

If you’re searching for a quality substrate, we recommend this aquarium sand.


The tank water needs to be well-filtered and heated. Don’t worry about water flow but do keep their water in pristine condition. If you’re interested in learning more about external canister filters, check out our guide.

Also consider covering power filter intakes with a sponge as snails sometimes get their heads and bodies trapped in the slats. They can get seriously injured or killed.


Despite their slow pace, Assassin snails are one of the more active snail species out there. They like to explore tanks in search of food, often crawling on rocks, plants, and the walls of the tanks. You really have lots of options here. Including a cave or two will provide lots of varied surfaces for your snails.


Some snails are plant assassins. Not the case with the Assassin Snail. They generally aren’t bothered by plants and because they’re carnivorous, they will leave your plants alone. This makes them ideal for your planted tank. Java Fern, Anubias, Amazon Swords, and Hornworts are all great options.

Assassin Snail: Potential diseases

If you’re a first-time snail owner, it is important to know that snails can get diseases just like a fish can.  There are a number of issues that can occur with their shells:

  • White spots on their shells. This is like ich of snails. The white spots are likely parasites that have latched on to the outside of the shell. Lots of different parasites use snail shells to travel so keep an eye on shell health to keep parasites down.
  • Weak shells. Weak shells are a danger to snails. If their shells crack and their internal bodies are exposed, this will likely result in death.
    • Calcium is a good way to counterbalance weak shells. Calcium is important for hard shells. Snails get calcium from their diet, but you can also add calcium supplements into the water.

One word of warning with Assassin snails (and any type of invertebrate) is the use of copper in the tank. Copper is toxic for most invertebrates. Check the contents of any tank additions. It can get tricky because medications often contain some level of copper so if you have a community tank, be careful as you take care of all of your tank inhabitants.

Assassin Snail: Feeding

Assassin snails typically feed at night, unless you train them to feed during the day.

What do Assassin snails eat?

Being carnivorous snails, their preferred meal is other small snails. They help you deal with a snail infestation. Their preferred meals are Malaysian Trumpet Snails, Ramshorn Snails, and pond snails. Their successful feedings will be evidenced by empty snail shells around your tank. However, they will also eat fish flakes and pellets, which are usually high in fish meal. 

Assassin Snails also enjoy meaty items like Brine Shrimp or Bloodworm cubes. You can also mix if up with fresh slices of fish or beef heart; they’ll go crazy over these options. In tight quarters, they will catch the scent and immediately make their way to the food. 

Similarly, if one of your tank inhabitants dies during the night, you may find the dead fish covered in Snails in the morning. Sometimes people mistakenly believe that the Assassin snails killed the fish in the middle of the night but rest assured – Assassin snails might be killers but they’re not speedy nor crafty enough to kill your fish.

Assassin snail shells

Assassin Snail: Tank Mates

From the Assassin perspective, they will basically ignore all fish that you add to the tank. However, there is risk involved with fish species who like to snack on snails. 

Most community fish are excellent tank mates. Small species that swim in the mid-levels of the tank are good choices: 

Other good options include: 

  • Angelfish
  • Corydoras catfish 
  • Otocinclus catfish

Avoid the following tank mates:

As for snail tank mates, avoid housing Assassins with any snails you plan to keep. Even large snail species, such as the Apple Snail, are at risk, as Assassins are known to gang up on a bigger snail.

Assassin Snail: Breeding

Assassin snails are regular breeders in captivity, so if you want to increase your population, there is a good chance you can be successful. Assassin Snails reproduce in freshwater by laying eggs. They’re not hermaphrodites like a lot of other snail species so you will need a small group (5 or 6) to make sure you have both males and females. Males and females are virtually indistinguishable so it is a numbers game for successful breeding.

To encourage mating, no special circumstances are needed. It is recommended to avoid low water temperatures, as it reduces their activity levels and metabolism. Overly active tank mates could also reduce the likelihood of breeding, as they can stress the snails.

Courtship and Breeding 

Courtship is a simple affair. Assassins will couple up and follow each other around the aquarium for 12 hours or so. This is a stark difference from normal behavior, as most of the time, your snails will completely ignore one another.  If you’re awake during this period, you might catch a glimpse of two snails stuck together.

Egg Laying

Once they’ve mated, the female will lay tiny eggs, one at a time. She will attach them to hard surfaces like aquarium glass or driftwood. After about 30 days, the eggs will hatch to release juveniles. These baby snails will immediately burrow into the substrate until they’ve grown. You’re unlikely to see them again until they’ve matured (in about 6 months).

Baby Assassin Snail Care

Juveniles will burrow into the substrate until they’ve grown. You’re unlikely to see them again until they’ve matured (in about 6 months time). Don’t worry about the adult Assassin Snails eating the babies; they tend to ignore their own kind as potential prey. However, the babies can be picked off by hungry tank mates, especially bottom-feeders who spend all of their time near the substrate.

Assassin Snail FAQs

How many Assassin snails per gallon?

It is recommended to have no more than 2 Assassins per every 5 gallons in your tank, so approximately 1 Assassin for every 2.5 gallons.

How does the assassin snail kill?

Assassin Snails have a mouth and radula (similar to a tongue) that they stick into their prey’s shells. The radula rubs the prey’s shell thin, to the point where their mouth can eventually reach the flesh of their prey. Assassins hunt by scent. They will sometimes team up to take down larger prey,  so even your Apple snails might not be safe.

Are Assassin snails dangerous?

It depends on who you’re asking. They’re dangerous to other snails in your tanks. They’re not dangerous to fish or humans.

What do you feed Assassin snails?

Assassin snails are carnivores, not algae eaters like a lot of snails. Living up to their names, Assassin snails prefer to eat other snails, such as Ramshorn or Malaysian Trumpets. They will also eat fish flakes and pellets. They enjoy meaty items like Brine Shrimp or Bloodworm cubes. They will also scavenge in your tank so if a fish or shrimp dies, you can expect to find it covered in Snails in the morning. 

Why do Assassin snails bury themselves?

Assassin snails, like assassins, often work by stealth rather than speed. They hunt for live snails by burying themselves and waiting with their proboscis (feeding tube) sticking out. When an unsuspecting prey gets close enough, the Assassin snail emerges and attacks. They also sort of rest and relax for a bit after eating, so they might disappear for a while after a good meal.

Do Assassin snails get overpopulated?

It is possible for Assassin snails to get overpopulated. Their population will grow as long  as there is a regular food source to sustain them. However, Assassin snails are typically self-sustaining, as members will die once the food source can no longer support them, which typically balances things out. 

Will an assassin snail eat a Nerite snail?

Yes, it is possible for an Assassin to eat a Nerite snail. But nerites are not a preferred prey as they’re difficult to eat due to their operculum which provides partial protection. However, left with no other options, Assassins will go after Nerites. 

Where do Assassin snails lay eggs?

Assassin snails lay eggs on the hard surfaces of tanks, such as aquarium glass, rocks,  or driftwood.

How long can Assassin snails live out of water?

Assassin snails can survive up to 36 hours out of water. Sometimes they crawl out of water or tanks so there is a little leeway if you catch them making a break for it.

Do Assassin snails clean tanks?

Assassin snails are carnivores and therefore do not eat algae like most snails. However, they do help clean tanks by keeping other snail populations under control.

Will Assassin snails eat shrimp?

Yes, Assassin snails do eat shrimp. However, it is not common. Assassin snails can’t catch anything that is faster than them, so shrimp and fish are typically safe. However, if a shrimp is sick and slow, or dies during the night, Assassin snails will absolutely eat it.

Is the Assassin Snail Right For Your Aquarium?

Now that you’ve learned just about all there is to know when it comes to caring for Assassin snails, you should be able to decide for yourself if they’re a good fit for your aquarium.

Assassin snails are great for helping you keep other unwanted pest snails under control, naturally. They’re carnivorous snails who love to snack on Ramshorn Snails, pond snails, and Malaysian Trumpet snails.They’re a peaceful community tank member, as long as the other tank members are fish and shrimp. Other snails – you’ve been warned!

If you can accommodate their need for other snails to eat, they can make very functional additions to your tank that will help keep your tank happy and healthy with sustainable snail populations.

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