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SnailsAssassin snail (Clea helena) | Care & info
Snails in the aquarium are fun and all, but some just multiply a little too quickly. If you've found yourself with a snail plague on your hands you might be wondering how to get rid of the annoying things. After all, they're not harmful, but they sure aren't pretty to look at!
Most snail-eating fish get much too large for the average aquarium or are overly aggressive, but don't despair. The solution is here, and you might be surprised to hear that... it's a snail.
| Scientific name | Clea helena |
| Common names | Assassin snail, snail-eating snail |
| Difficulty level | Easy |
| Origin | South-East Asia |
Table of Contents
Assassin snail natural habitat
The assassin snail, also known as the bumblebee snail, is one of the only freshwater members of the family Nassariidae, a specific type of whelk also known as Nassa mud snails.
Whereas most of its cousins inhabit marine and brackish environments, the wild assassin snails are naturally found in rivers, ponds and lakes throughout much of Southeast Asia. As ambush predators, these freshwater snails spend most of their time buried in the substrate.
Did you know? Scientists have waffled for a while now over the correct scientific name for this species. Both Clea helena and Anentome helena are now considered acceptable, but we wouldn't be surprised if more changes are made to these genera in the future.
Invasive potential
We're proponents of sustainable fishkeeping here at The Shrimp Farm, so we feel it's important to note that several scientific studies have pointed at the assassin snail as a serious potential pest.
If they get loose and manage to establish themselves in areas outside of their natural habitat, they can become a threat to other freshwater snails. Additionally, they may carry non-native parasites that can damage the local snail population as well as other animals.
Never release any aquarium fish or invertebrates into the wild!
Assassin snail appearance
Clea helena is definitely not the most inconspicuous assassin out there. Its bright yellow and dark brown banded trumpet shell is sure to draw attention!
This means that even if you're not looking to have it massacre pest snails, it'll still be a colorful addition to your aquarium. With a maximum size of around 0.5", it doesn't need a large set-up.
Setting up an assassin snail aquarium
Assassin snail requirements
If you're interested in acquiring a few assassin snails, tank size is not much of an issue. Nano fish tanks of 5 gallons or up should be absolutely fine for one or two or these snails. Anything smaller might not hold a steady cycle, causing water parameters to fluctuate.
Your assassin snail aquarium should be filtered, fully cycled and heated. The snails don't have any specific demands when it comes to décor, although we recommend a planted tank, as live plants make it easier to maintain healthy and stable parameters.
Assassin snails naturally inhabit waters with a soft substrate where they can hide and wait for unsuspecting prey, but aquarists have found they generally do just fine on gravel as well.
Assassin snail water quality
Assassin snail care is pretty straightforward. In the wild, they're among the only members of their genus that can thrive in stagnant waters like ditches rather than exclusively inhabiting fast-flowing streams. It's thought that they've evolved to withstand less-than-ideal water parameters, which is why they do so well in the aquarium.
The most important factor to keep in mind for any snail (besides the nitrogen cycle) is water hardness. Snail shells are comprised of calcium, meaning that very soft water can actually cause a snail's shell to begin deteriorating in the long run.
This can eventually become fatal, so be sure to keep the pH relatively high and your water on the harder side.
pH: 7.5-8.5
Temperature: 75-80 °F
Assassin snail tank mates
If you want to keep assassin snails, you must choose their tankmates wisely. As you've probably guessed by now, these are active predators that will snatch anything they can catch.
Now, they're not that fast, so they won't be able to harm fish and larger inverts (even bottom feeders), but care should obviously be taken when combining them with other snails.
Snails
Smaller snails (and not just pest snails!) are bound to get eaten sooner or later. There is a bit of ongoing discussion on snail safety and whether other snails like ornamental Nerites are safe, we'd personally rather not find out.
Shrimp
There is some debate about whether assassin snails are shrimp safe or not. Some hobbyists do report their assassins catching shrimp fry, although they probably don't damage your shrimp population all too much.
Still, if your tank contains expensive shrimp or if you're working hard on multiplying your stock, you might want to pass up on this killer snail.
Fish
You can keep assassin snails with various fish species. Just make sure to avoid fish that have a taste for snails, like clown loaches and pufferfish, as those will make an easy meal of your assassins.
Assassin snail diet
You probably won't be surprised to find out these snails are mainly carnivores. Their natural diet consists of snails, snail eggs and anything else that floats by their sandy hiding place - alive or dead.
This being said, assassin snails will also eat algae, plus any leftover fish foods and shrimp pellets they can find. A hungry assassin snail will also happily consume dead fish.
Feeding assassin snails is easy: you can supplement their diet using commercial fish foods, like fish flakes, as well as frozen foods like blood worms or brine shrimp. If you're serious about assassin snail care (if you're trying to breed them, for example) you can even set up a separate snail breeding container to ensure this natural food source is always available.
Don't forget: removing excess uneaten food within a few hours helps keep your water parameters stable.
Did you know? Assassin snails have sensitive "noses". They're able to sense prey or carrion and will quickly emerge from the substrate if any dead organisms or edible snails are nearby.
Pest snail control
In the aquarium, their carnivorous nature is one of the main reasons people keep this invertebrate. The assassin snail feeds on unwanted pest snails (including Malaysian trumpet snails, ramshorn snails, pond snails and others), sometimes actually ganging up on larger snails in groups and leaving nothing but empty snail shells behind.
Aquarists have asserted that their assassin snails prefer eating trumpet snails, but generally speaking, they'll go for any species they can catch. You'll also see yours eating snail eggs, further helping to keep any infestations under control.
As such, if you're dealing with pest snail population explosions, assassin snails can make a good solution. Do keep in mind that you should also deal with the underlying cause of the infestation, usually overfeeding, to fully resolve the issue.
Assassin snail breeding
Breeding assassin snails is just easy enough to be an enjoyable project for beginners, but just difficult enough to avoid ending up with another snail infestation. Even if you do end up with a larger snail population than you wanted, you'll usually be able to sell them pretty easily.
All you have to do in order to get your assassin snails breeding is get a group that's large enough to guarantee the presence of both males and females. It's not possible to tell the difference between the boys and girls visually in this snail species, so you just have to hope you get both!
Feed high-quality, nutrient-rich foods and make sure the water quality is always high. Adult assassin snails will take care of the rest and start producing egg sacs once they're sexually mature.
Assassin snail eggs are laid one at a time, totaling up to four per clutch. Baby assassin snails hatch after around two months, tiny but fully functional. They'll spend much of their early life hiding in the substrate and feeding on tiny edible particles, but will emerge to eat snails as soon as they're large enough.
Frequently asked questions
Not really, as they're mostly carnivores. Try some red racer nerites for algae control!
It's unlikely for an assassin snail to attack and kill a larger mystery snail, but we're not going to say it's impossible either. Consider the risk before combining the two.
Since nerites aren't very large, this is definitely a possibility. These two species are not a good combo!
Buying assassin snails
These useful snails have found their way into the mainstream aquarium hobby. You should be able to find them at some aquarium stores and there are also plenty of hobbyists out there selling a snail or two.
If you don't want to leave the comfort of your home just to go out and buy a few snails, you can easily order these assassins online at The Shrimp Farm. Buy your snails here!
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