Can Hermit Crabs Breathe Underwater?


by Simon Griffiths


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Water is essential for the survival of many living organisms. In this article, we will talk about hermit crabs and their relationship with water. We will talk about how much water they need to survive, why they need this water, and how much water is too much. Many people have lost their hermit crabs to drowning, so this information is important.


Can hermit crabs breathe underwater?

Land hermit crabs

Land hermit crabs breathe through their modified gills. They need them to draw oxygen from the moisture in water, which is why they always make sure to live near water when they are in the wild. Their gills must remain moist.

Even though they need water to breathe, they cannot stay submerged for too long. As mentioned in the introduction of this article,  land hermit crabs sometimes drown under the care of people who keep them as pets. 

Their ability to breathe underwater is dependent on their size and species. It has been claimed that bigger hermits can probably stay submerged for an hour and survive. Other people say that the ones that can go as long as an hour need to come up for air from time to time. Most people suggest that they can stay submerged for 20 to 30 minutes.

For the safety of your pet, make sure that they have an easy way out of the water that you put in their tank to keep them from drowning.

Marine hermit crabs

For aquatic or marine hermit crabs, the water is their home. This means that they will have no problems breathing underwater at all.

So how do they breathe?

As we already mentioned, they breathe through their gills. Their gills are found under the carapace, which is the dorsal section of their exoskeleton, in the brachial chamber. They have appendages known as scaphognathite, which help them to draw water to their gills by osmosis and extract oxygen from the moisture. Carbon dioxide is then expelled through their mouths through bubbles.

Uses of water for hermit crabs

Hermit crabs need both freshwater and saltwater. Some of the uses of water for hermit crabs include;

1. A home 

Hermit crabs come in over 800 species; most of them are aquatic, some semi-terrestrial and terrestrial, and only one species is a freshwater species. For aquatic hermit crabs, water is their home. They will come to land for brief periods at a time, to look for mates and food. Some of them do not even come to land at any point during their lifetime. Marine hermit crabs live on ocean beds primarily in shallow waters.

Related  What Do Hermit Crabs Need In Captivity Apart From The Tank?

2. For Drinking

Hermit crabs need to drink both freshwater and saltwater. If you have a pet hermit crab, try to put out both in their tank to drink. Make sure it is in a container that is easy to reach and climb out of. Hermit crabs can drown, so make sure the container is easily maneuverable by adding a ramp, pebbles, or a net, especially if you will be away from them for a long time.

You can make salt water by adding aquarium salt to bottled water. The sea salt has to be the type that is specifically sold for crustaceans, not iodine. Iodine is harmful to hermit crabs. Not all bottled water is safe though, some of it still contains some chlorine, which can kill hermit crabs. The safest bottled water option is spring water.

To have fresh water, you can use conditioned tap water that has been treated by a de-chlorinator. Pure tap water has harmful amounts of chemicals and heavy metals that can kill the hermit crab and damage its gills. You can also boil tap water and leave it to sit for a while so that some of the chemicals can evaporate, but conditioning the water is a better and safer option.

Related How To Make Safe Saltwater for Hermit Crabs

3. Respiration

Hermit crabs do not breathe oxygen from the air directly, they breathe it from water. They have gills for breathing to help them draw oxygen from moisture, which is why their gills must always be hydrated. They expel carbon dioxide through their mouths.

Land hermit crabs have evolved to have a branchiostegal lung, which is small but helps them absorb air easily and regulate their breathing. If the gills are not moistened from time to time, they will develop scars and constrict, which eventually suffocates them.

Marine hermit crabs will suffocate when outside water because their gills dry out quickly. 

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

4. Molting

For hermit crabs to grow, they need to molt. They shed their exoskeleton and grow a new one to accommodate their body size every time they molt. During this time, they drink and store a lot of water.

This is because they burrow in the sand so that they have privacy and safety during this time when they are at their most delicate and sensitive. This water helps them to survive this period and it is useful in building hydrostatic pressure for the disintegration of the old exoskeleton.

Related How Long Does It Take A Hermit Crab To Molt 


Can I bathe my hermit crab?

Yes, you can!

In the wild, land hermit crabs will submerge themselves in water for a post-molt soak or rinse out their shell.

For your pets, bathing them in salt water meant for crustaceans is essential for their well-being. It helps them hydrate their gills, store some water in their shells, and stay free from mites. The frequency of bathing them depends on the prevailing climate conditions.

Let’s start with humid areas. In the summertime, you can bathe them twice a week. During the rest of the seasons, one week will be enough.

In dry climates, try to bathe them in salt water every other day.

Bathing them shouldn’t be too difficult. Just prepare the salt mixture with the appropriate type and amount of  Hermit crab salt or ocean salt and put them inside. Make sure you use slow and gentle movements to avoid scaring or stressing the crabs. After swishing it gently in the water, leave it alone for some time.

Can Hermit crabs breathe under the sand? 

Hermit crabs love the sand. They need it to destress, and protect them from excessive heat and light, and in the wild, they need to burrow in sand to keep themselves safe from predators.

During molting phases, they prefer to burrow in the sand for privacy. They will usually create a tunnel to let in air so that they are able to breathe.

If you have a pet hermit and you are worried when it retreats in the sand, do not worry because this is normal. As long as you use the appropriate substrate, it should be able to breathe just fine.

How do I help my hermit crab to destress?

Sometimes hermit crabs become stressed when their surrounding conditions are not conducive or when they become sick. 

To help your hermit crab to destress, try changing its food and make sure it is fresh. You can also switch their water and make sure they have both freshwater and saltwater. Check the temperatures and humidity in the tank as well to make sure it is at the right levels.

You can also inspect them to check whether they are sick or not.

Conclusion – Can hermit crabs breathe underwater?

This is the end of the article, hopefully, you found what you were looking for.

In summary, marine hermit crabs can breathe underwater because it is their home and their gills enable them to do so. Land hermit crabs can only breathe underwater for a few minutes, not exceeding an hour.

So make sure you are careful when you leave your hermit near water unsupervised. Make sure it can make its way in and out safely.

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.

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