Can Hermit Crabs Drown Underwater Yet They Have Gills?


by Simon Griffiths



One of the most contentious topics about hermit crabs is if they can drown in water.

That’s why most hermit crab owners are concerned about the size and depth of their saltwater and freshwater pools to mitigate the risk of their pets drowning.

But what are the facts?

This post answers the question, can hermit crabs drown, yet they have gills? This post gives you peace of mind and will help you take better care of your hermies.

And it’s probably not what you expect.


Can Hermit Crabs Drown?

Yes, hermit crabs can drown in water if they are trapped with no way out. This is because land hermit crab’s respiratory system adapts to breathing on land and hence cannot breathe in water. However, hermit crabs can stay submerged in water for up to 45 minutes without breathing depending on the species and age. The hermie will eventually move out of the water to catch a breath.

How Easy Is It for Hermit Crabs to Drown?

No, a hermit crab will only drown if it gets trapped underwater. This happens when there are no means to get out of the pool. The depth of the pool does not pose a drowning risk provided there is an accessible way out. A hermit crab knows when to get out of the water to catch a breath. 

Should you remove the water pools to remove the drowning risk?

No, freshwater and saltwater pools are a requirement for crabs and they will get sick and eventually die if you fail to provide it them. However, there are some species that don’t require both fresh and salty water like the PP.

can hermit crab drown?

Can Hermit Crabs Breathe Underwater?

No, hermit crabs don’t breathe underwater. This is because of the adaptation that hermit crabs go through in order to survive on land. Studies show that land hermit crabs’ gills adapt and get smaller and also develop lungs to be able to breathe on land (branchiostegal lung). This changes their breathing from water diffusion to air perfusion “branchiostegal lung”

Despite the adaptation, land hermit crabs still require enough humidity to keep the gills moist to be able to breathe. This is why saltwater and freshwater pools are a must-have in any crabitat. 

If the modified gills are submerged in water for more than an hour, the hermit crab will run out of breath. This simply means that the gills of a land hermit crab cannot function in water.

All they need is enough moisture around their habitat and they’ll breathe smoothly.

Related Can A Hermit Crab Breath Underwater and Does it Breathe Water or Air?

how long can a hermit stay underwater

How To Prevent Your Hermit Crabs From Drowning

As much as you are required to have two pools in your hermit crab’s habitat, you should not ignore the fact that they can easily drown. And as you well know, drowning is one of the causes of hermit crab deaths.

Fortunately, there are some steps you can take to curb any cases or possibilities of drowning. Below are a few proven ways to reduce cases of drowning:

1. Use A Pool Ramp

If you are thinking about setting up a swimming pool, it should be in your best interest to include a pool ramp. The ramp should be nicely placed in order to help the hermit crabs out of the pool whenever they feel like it.

Make sure the ramp is made from a material that won’t become slippery when wet. You can use rough plastic as a ramp, but avoid using metal as it can easily rust. The best strategy is to improvise your own pool ramp at home. All you have to do is secure it to the swimming pool firmly.

2. Make your makeshift pools easy to navigate

If your hermit crabs can’t navigate their swimming pools in an easy manner, then you risk them drowning. It is advisable for you to reduce the number of decorations you plan on using in the pool. Make it easy to navigate by just using some of the basic décors.

Avoid situations where your hermit crab can accidentally become trapped in the swimming pool or even in their water dishes.

3. Use Shallow Pools & Water Bowls

Although pools and bowls should be deep enough for your hermit crab to fully submerge, they should not be too deep. The depth should be ideal enough for your crab to submerge and emerge without facing any difficulties.

Of course, the size of your crab will determine the bowl or pool size you should go for. For reference purposes, you should measure the height of your crab as it will help you determine the best depth. A crab that is 3 inches can do well in a pool that is 5 inches deep.

This article on hermit crab sizes should help you determine how big your crab can get.

Can Hermit Crabs Swim?

Unlike some crabs that can swim thanks to their swimmerettes, hermit crabs can’t swim. They are decapod crustaceans and their heavy shells would not allow them to swim or stay afloat. This is because hermit crabs’ legs are not adapted to swimming. When in water they will either walk or run. 

But what do hermit crabs need water for if they can’t swim?

Good question!

But to clear things up, the water is not placed there for the crab to swim.  Water is an important part of a hermit crab’s diet. Besides, pet crabs need to take a bath and replenish their shell water. This is why you have to provide them with a bowl of both freshwater and saltwater.

Hermit crabs will submerge themselves as long as they wish, and they will slowly walk out of the water dish once they are satisfied. You won’t see your crabs swimming in their pools. They’ll most likely stand and soak their bodies and shells as opposed to wading through the waters.

That said, you should never try to take your hermit crabs for a swim. They don’t need to swim and you should never force them to do so.

Frequently Asked Questions On Whether Hermit Crabs Can Drown

Can hermit crabs breathe underwater?

Unlike us humans, adult land hermit crabs can withstand being underwater for up to one hour before they drown. So typically, these crabs can hold their breath for between 15 to 45 minutes when still submerged in water. Beyond that time frame, the hermit crab will run out of breath and die. The crab’s instincts will tell it when it should move out to take a breath.

How long can hermit crabs stay underwater?

When submerged underwater, a hermit can stay up to 45 minutes without breathing. The hermit crab will then get out of the water, take a breath and sometimes go back inside the water. Some owners report their hermies staying in the water for up to 5 hours when preparing to molt. They will come out of the water briefly to breathe and will go back inside the water.

Can hermit crabs live underwater?

No, hermit crabs cannot live underwater since their respiratory system adapts to living on land. That’s why hermies will drown if they are trapped underwater. Luckily, their instincts will alert them when it’s time to get out to catch a breath.

How long can hermit crabs go without water?

Without access to fresh and salt water, a pet land hermit crab won’t survive for more than two weeks. Hermit crabs require water to keep their body and gills moist, which maintains proper breathing. See our detailed article on how long hermit crabs can last without water.

Do hermit crabs live in water?

No, the 17 species of terrestrial hermit crabs don’t live in water. While female hermit crabs lay their eggs in the water and the babies still hatch in the water, they eventually come to the land when they adapt to life on land. The main adaptation they go through is the ability to breathe on land, which takes away the ability to breathe underwater. See our detailed article on whether hermit crabs live in water

Wrapping Up

By employing the above strategies, you won’t have to worry about your pet hermit crabs drowning. At least you’ll give them the chance to live for a long time and become happy.

Simon Griffiths

Hi guys, my name is Simon, a fellow pet lover. I love everything about traditional and exotic pets so I am here to help you create a better home for your pets.