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Do Crabs Eat Snails?

A large number of fish keepers are starting to also keep crabs in their aquariums so we have noticed more and more questions about both freshwater and saltwater crabs and how they behave with other popular tank inhabitants.

Although the pet crabs that you see on social media look all cute and innocent, the majority of crabs are actually opportunistic hunters and will eat many of the common fish, snails, and shrimp in a community tank.

This is why we see so many questions each month about if you can keep crabs with certain tank mates. One of the more common questions that we have noticed people asking is if crabs eat snails or not.

There is actually a large amount of misinformation amongst various fish keeping social media groups about this with the common logic seemingly being that the snails shell will protect it from a crab.

This is not correct but does seem to be a very popular belief so we wanted to publish this article to try and help as many of our readers as possible who are thinking of keeping crabs and snails.

Do Crabs Eat Snails?

The majority of crabs will happily eat most types of snails in an aquarium. Crabs are usually smarter than people initially think to and can workout ways to pull the snail out of its shell but some species of crab are strong enough to just crush the snails shell with the snail in it.

Due to snails being very slow movers with relatively slow reaction times to a potential attack, most crabs will easily be able to eat them if they are hungry.

The majority of the popular crab species that are commonly kept as pets are omnivorous opportunistic hunters who will eat both plant and animal based food.

If the crab in your aquarium is hungry or bored then it may see the local snail population as a food source or a way to entertain itself.

Although unconfirmed, we have seen people theorize that some crabs will specifically hunt snails for the calcium in their shells to help maintain the crabs own shell.

If you do suspect that this is one of the reasons that the crabs in your tank are eating the snails in your tank then you can try feeding them cuttlebone.

Can Crabs And Snails Live Together?

It is usually not recommended that you keep crabs and snails in the same aquarium due to the crabs usually seeing the snails as a food source.

That said though, crabs can cause problems with slow moving fish, amphibians, and shrimp too as they will usually try to eat anything they can grab in their claws.

If you do want to keep crabs as pets, it is usually better than you keep them in an aquarium with other crabs or with larger, fast moving fish that swim in the middle or at the surface of the tank.

A common mistake that people make time and time again is thinking that a crab and bottom dwellers will be fine together only to have their bottom dwellers disappear a few weeks later as the crab has ate them.

We have seen some people on social media saying that their crab leaves their snails alone provided they keep their crab well-fed but this is circumstantial evidence.

Just like most things on social media, it should be taken with a pinch of salt and just because one person’s crab doesn’t eat their snails does not mean that yours will behave in the same way.

Why Do Crabs Eat Snails?

Crabs are opportunistic hunters and they will take any opportunity they can if they are hungry. Some crabs will also actively hunt the other inhabitants of their aquarium as a form of mental stimulation if their aquarium is too small for them and they get frustrated too.

Most aquatic snails are excellent sources of vitamins and minerals while also being a great source of protein too. If your crab’s diet is nutritionally deficient then it may eat the snails as a way to top up essential vitamins or minerals that are missing from its diet.

Some of the commercial crab foods on the market are close to being nutritionally complete for most species of crab so can deter this behaviour though.

As we touched on earlier in the article, there is a popular theory that crabs will hunt snails to crush their shells up and eat them as a source of calcium.

There could actually be some truth to this though as crabs do require a higher than average amount of calcium in their diets to maintain their shells but you can try feeding your crab cuttlebone due to it being an excellent, easy to eat source of protein.

Is There Any Type Of Crab That Will Not Eat Aquatic Snails?

Crabs are opportunistic omnivores meaning that they will seize any opportunity for food be it plant based or animal based. This means that the majority of crabs will probably turn their attention to the snails in your aquarium at some point or another and eat them.

Unfortunately, there really is little that you are actually able to do about this and the majority of the time you just have to accept it as it is the instinct of the crab.

As we covered earlier in the article, this is why so many people keep their pet crabs in their own tanks with very few other tank mates as most other animals are not safe with a crab in their aquarium.

This gots for both saltwater and freshwater crabs too. For some reason a rumor started a few years back about how freshwater crabs will not eat their tank mates but this is not correct at all. Both saltwater and freshwater crabs will eat anything they are fast enough to catch.


That brings our article going over if crabs eat snails to an end. We would highly recommend that you try to keep your crabs and snails in separate tanks else you will end up with fewer snails in your tank and a well fed crab. Due to many aquarium keepers taking advantage of snails as a way to reduce the algae build up and to reduce the amount of discarded fish food on the bottom of their tanks a healthy snail population can be advantageous.