Skip to Content

Why Is My Hermit Crab Outside of Its Shell? (9 Common Reasons)

Why Is My Hermit Crab Outside of Its Shell? (9 Common Reasons)
The purpose of this blog is to share general information and is written to the author's best knowledge. It is not intended to be used in place of veterinary advice. For health concerns, please seek proper veterinary care. In addition, as an Amazon Associate I earn from qualifying purchases.

Caring for hermit crabs in your home has the potential to be a lot of fun. These little pets are interesting to observe, and they aren’t that hard to care for overall.

You want to ensure that you do a good job of giving your hermit crab what it needs. After all, you want it to survive for a long time under your care.

This is why it’s so concerning when you see your hermit crab outside of its shell. You know that it’s not normal for a hermit crab to leave its shell.

Why would the hermit crab be outside of its shell? Is this a sign that something is wrong or that the crab is dying?

Continue reading to get more information about this topic. It’ll ensure that you will know what to do to try to help your pet.

Shell Evacuation

When a hermit crab leaves its shell, it’s known as shell evacuation. As mentioned above, this isn’t a normal thing for a hermit crab to do.

Once you notice that your hermit crab has evacuated its shell, it’s important to take action. Hermit crabs are incredibly vulnerable outside of their shells.

It could be a sign that you need to worry about the hermit crab. You’ll simply have to pay attention to what’s going on to get to the bottom of the situation.

Below, you’ll learn about several reasons why hermit crabs will leave their shells. This should help you to determine what is going on with your pet hermit crab.

1 – Is the Hermit Crab Simply Picking Out a New Shell?

Of course, there are situations where shell evacuation will be normal. For example, hermit crabs leave their shells when they’re trying to locate a new one.

You should always keep shells of different sizes in the habitat for the hermit crab. Hermit crabs grow over time and they’re going to need to switch shells when they grow.

If you have different shells in the habitat, the hermit crab will be able to walk out of its current shell and into a new one. Sometimes it takes a while for the hermit crab to find the perfect shell that it’s looking for.

This is why it’s imperative to buy a variety of different shells. You should have many different sizes so that your hermit crab can locate the right fit based on its current size.

You can buy hermit crab shells from local pet stores. It’s also possible to get what you need online.

If this is all that is happening, you don’t need to worry at all. Hermit crabs are going to change shells many times and it’s something that you’ll get used to.

2 – Issues with Stress

Sometimes hermit crabs will evacuate their shells when they’re really stressed. These creatures can become stressed for a number of different reasons.

One reason involves transporting the hermit crab. When you move the hermit crab from one habitat to another, it’ll be a stressful experience.

The crab might become very stressed and will start acting strange. If it evacuates its shell, it could just be a sign of stress.

Another thing that causes hermit crabs stress involves handling. Handling hermit crabs is not something you should do unless it’s necessary.

For the most part, you should avoid handling these creatures. You run the risk of stressing the hermit crab and causing it harm.

3 – Problems with Humidity

You should know that hermit crabs need high humidity levels to be able to breathe. This means that you should have some type of humidifier in the habitat for the crab.

When the humidity levels are too low, it’ll make it tough for the crab to breathe. In response, the crab might evacuate its shell to try to improve its condition.

It’s imperative to monitor the humidity levels in the habitat closely. You want to keep things in the right range for the crab.

You might not know this but the humidity levels can even be set too high. To help your pet hermit crab thrive, it’s best to keep the humidity levels in the habitat between 70 and 80 percent.

Use a hygrometer to keep an eye on things. Adjust the humidity levels as necessary to keep the hermit crab healthy.

4 – The Temperature Is Too High

Monitoring the temperature of the hermit crab’s habitat is important as well. Things can get too hot for the hermit crab if you aren’t careful.

If it gets very hot in your area during the summer, the temperature in the hermit crab’s habitat might get way too hot. The hermit crab could be fleeing its shell in an effort to get relief.

You’re supposed to keep the temperature of the hermit crab’s habitat between 72 and 80 degrees Fahrenheit. Allowing the temperature to go higher than this will be detrimental.

Keep the hermit crab in a temperature-controlled environment to avoid such issues. It shouldn’t be hard to keep the temperature in the right range for most people.

5 – Issues with Fighting

Perhaps you have multiple hermit crabs in the habitat living together. Hermit crabs can get along with each other just fine.

However, it’s also normal for hermit crabs to fight over certain things. This is especially true when it comes to shells.

Two hermit crabs might wind up fighting one another over a shell. It might be that the shell is the perfect size for both crabs.

Neither will be willing to give it up, so one crab might fight the other to force the crab out of the shell. If you see one of the crabs out of its shell, it could be that something like this occurred.

Prevent issues like this by giving the hermit crabs plenty of shells. You should have two or more of each shell size to keep the hermit crabs happy.

This will give them no reason to fight each other over shells. There will be plenty of hermit crab shells to go around.

6 – Fungal Growth

There could be a fungal growth inside of the hermit crab’s shell. This would force the crab to evacuate the shell.

Fungal issues will pop up when the hermit crab’s habitat doesn’t have good airflow. It’ll make it so that fungus is able to grow inside of the tank, and it can also grow in the shell.

It’s also important to feed hermit crabs fresh food. You don’t want the food in the habitat to become moldy.

Remove food from the habitat before it gets too old. If you do this, you should be able to prevent issues with fungal growth.

7 – Bacterial Growth

Bacterial growth issues are pretty much the same as the fungal growth issues mentioned above. A hermit crab could be forced to evacuate its shell due to the presence of bacteria.

This will be a bigger problem when you don’t have enough ventilation in the habitat. You also need to do a good job of keeping things clean.

If you’ve been lackadaisical when it comes to cleaning, that could have caused bacteria to grow in the habitat. Do your best to clean and maintain the substrate to avoid such issues in the future.

You should be able to turn things around if bacteria is to blame for the shell evacuation. Just be mindful of the need to keep things clean and avoid making it easy for bacteria to grow in the habitat.

8 – Mites

Mites are a very common parasite that will bother hermit crabs. These pests are microscopic and can be incredibly difficult to see with the naked eye.

You might notice tan and black flecks on the crab. These are the mites, and they can cause your crab serious issues.

When left alone, mites will stress hermit crabs and can even injure them directly. Sometimes crabs with lose legs due to mite infestations.

Some crabs will even wind up dying. Thankfully, you can get rid of the mites by taking the right actions.

Submerging the crab in water should get rid of any mites on its body. You can then place the hermit crab in a holding tank while you vacuum the habitat.

Vacuuming the habitat can help to get rid of mites. You can also wipe down the habitat with water to eliminate the mites.

9 – Problems with Foreign Material in the Shell

It could even be something as simple as foreign material getting stuck in the shell. Sometimes hermit crabs will become uncomfortable if sand or other debris gets stuck in the shell.

The crab might leave the shell to try to find another one. Or it might want to get the sand out of the shell so it can be more comfortable.

This isn’t likely anything to worry about. The crab should go back inside of a shell and everything will be fine.

Hermit Crab Out of Shell Looks Dead

What if the hermit crab is out of its shell and it looks dead? Is this a sign that the worst has happened?

Don’t jump to conclusions just yet. It could be that the hermit crab is molting or getting ready to molt.

Often, molting hermit crabs will protrude from their shells. They will usually look limp and lifeless during this time.

If you look carefully, you might be able to see it twitching a bit. This is a sign that it’s alive.

Sadly, it can be hard to tell the difference between a molting hermit crab and a dead hermit crab. Also, sometimes hermit crabs die while they’re molting.

The big problem with this is that you can kill the hermit crab by scaring it to death. Therefore, you don’t want to disturb it to try to see if it’s alive.

If the crab starts to smell really bad over the course of several days, it’s likely that it has perished. Just give it some die so that you don’t accidentally kill the crab when it’s simply trying to molt.

Tips for Placing Shells in the Tank

You learned earlier that you’re supposed to give the hermit crabs options when it comes to shells. If the hermit crabs don’t like the shells in the tank, it might be harder for them to figure out what to do.

There are some tips that will come in handy that can help you to make things easier for the hermit crabs. Firstly, it’s wise to buy shells that suit the hermit crabs.

Take note of the type of entrance that the hermit crab’s current shell has. Try to buy shells that have the same type of entrance since those might appeal to the hermit crab more.

It’s also important to take the time to pick out shells that are safe for the crabs. You can’t use painted shells and you want to buy natural products from respected vendors.

Don’t put new shells into the habitat right away. Take the time to brush them off and ensure that no debris is present inside of the shell.

The shells should be sterilized for twenty minutes before being put in the habitat. This can be done using boiling water.

You will be able to dry the shells and then place them in the habitat when you’re done. It’s recommended to mist the shells with dechlorinated saltwater.

Final Thoughts

You’ve learned a lot about hermit crabs and why they might evacuate their shells. There are truly many reasons why this might occur.

Many of the reasons why this happens will be problematic. It could be that your hermit crab is dealing with parasites such as mites.

If this is the case, you’ll need to take action fast to protect your pet. The same is true if fungal growth or bacterial growth are to blame for the shell evacuation.

It could also be a simple case of the hermit crab needing to switch shells. Perhaps you need to present the hermit crab with more options.

If you have multiple crabs in the habitat, it’s important to have two shells of each size. You don’t want the crabs to fight over one shell.

Keep all of this information in mind. You’ll be able to make good choices that will help you to protect your hermit crabs.

These pets rely on you for care and protection. Do your best to ensure that they can thrive by monitoring the temperature and humidity of the habitat carefully.