Molted Hermit Crab: 4 Important Molting Processes That You Need To Know

molted hermit crab
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Are you looking to learn about Molted Hermit Crab? Our detailed article below will tell you all the information related to this stage. Check it out!

Molted Hermit Crab: Everything You Need To Know

Hermit crab is a notable crab species with exciting characteristics and appearance, so many people have chosen to bring it as a pet. These crabs grow every day and grow by molting. Let’s learn about the growth process of these animals and how to take care of them effectively!

Molted Hermit Crab – Why Hermit Crab Molt?

Under normal conditions, these hermit crabs will only molt when it is time to develop. Usually, this process will happen a few times a month when they are young and less when they reach adulthood. 

However, there are still some exceptional cases. You can see this crab molting even when not in the development process. So let’s find out why Hermit Crab Molt.

When it’s time to grow

Although it is a hermit species living on clams and shells, it is still a crustacean, so it still has an outer shell. This shell will hug the body so that when the crab grows, it needs to peel off the old cover to have space to grow.

By the time of molting, the crab will become soft. At this time, the crab will absorb water and nutrients to regenerate a new shell. At the same time, it is also when the uncle grows up and has an increase in size.

When it has an injury

Having an injury is not one of the good reasons for a crab to get a new shell. However, the molting process will be more straightforward when the crab is injured, such as a broken claw or part of the shell. The time for crabs to change to a new shell will also be faster, and this is an opportunity for the hermit card to heal and regenerate itself.

During reproduction

The molting process during reproduction usually takes place only in female gill crabs. Removing the hard shell increases the success rate of the mating process but increases the chances of fertilization.

The size of the follicles during pregnancy will change, and shedding the shell now will make the pregnancy process easier. However, this spawning molt only occurs in the wild as this crab will lose its ability to reproduce in captivity.

The Molted Process

The molting process of a hermit card can last up to weeks but can be summarized into 4 main stages: pre-molting, molting, post-molting, and regeneration. Let’s find out what each step of hermit crab’s molting will be extraordinary.


It will be difficult for you to see the change too clearly at the first stage. In between the flesh and the shell begins to form a new shell. For example, if a crab has an injury and loses a particular part, it will also begin to form again during this period. At this time, the crab will also actively store necessary minerals or store food and water.


This stage is the fastest and can see the change most clearly. The crab will separate its body from the old shell and slowly crawl out. Sometimes they will use pressure to crack the shell to get out more quickly.

After the makeover

After getting rid of the old shell, the new shell has not formed clearly and firmly, so the hermit crab needs to add minerals. It will return to directly eat the crust it has just escaped to supplement nutrients, support the calcification process. In addition, its parts will also gradually harden and recover the ability to move.


The final process is also the one that takes the longest for a newly molted crab to return to its normal state. It takes a long time for the new shell to accumulate calcium and minerals, to form, and for the shell to harden. 

Fortunately, the molting process only occurs frequently when the crab is young, and the frequency of molting will also decrease as the crab gets older.

Signs Of Preparation For A Molting

Before the start of a particular period, the Hermit crab or any other creature will also have unusual changes. There are also signs that you need to pay attention to know that they are about to start the molting process in this crab.

Diet changes

Don’t be too surprised if you see hermit crabs eating more than usual because they need food storage. If you keep hermit crab, you need to pay attention to adding saltwater at this time. They need to store large amounts of water to sustain life and still grow to break their former shell.

You can observe their belly turning black and gray, which means they are storing food. Some people call the belly part the fat pouch is a storehouse of nutrients and water. Apart from this stored food, they can’t do anything or look for other food until the shell regeneration is complete.

The crab is no longer as flexible as usual

The activity level of hermit crabs will also change when preparing to enter the molting process. After working hard for food, they will suddenly stop eating and become comatose for a few days. Many inexperienced people think they are dead, but this hermit crab is just a natural response.

Crabs that don’t have the ideal molting environment and conditions may react worse than usual. The time spent hiding in the shell may also be longer and not communicating with the outside world.

How To Make Saltwater For Hermit Crabs

Initiate the act of digging

Before starting the molting process, the hermit crabs will also dig up the sandy soil to bury themselves in it. It is a sign of crabs preparing to molt underground. If the average soil in the tank you keep the crabs in is not deep enough, or the soil is too hard, a lot of gravel can be a hazard for hermit crabs.

Most of these crabs have a habit of digging to find a place with prolonged darkness to protect themselves. The dark or perfect underground is also a way to avoid dangers from other crabs or other species in the wild. In addition, darkness is also the agent that helps them secrete hormones to regenerate a new shell.

In case the soil is not deep enough for hermit crabs to bury themselves, they can still perform the molting process on the ground. However, if you are in a natural environment or keep many different creatures, this is a danger for crabs. When molting, this crab emits a scent that attracts the attention of other crabs.

More giant crabs can come and eat away the old shell, quickly leading to the crab being molted to death due to lack of substance. 

Small crabs can easily hide but with giant crabs, when it comes to molting in unsafe conditions, it can become a meal for other species. So, if you realize this, you need to create the best conditions for the crabs to develop. You should isolate the molting baby until it returns to a normal state with enough shell to protect itself.

Change in appearance

Observing the hermit crabs regularly will quickly notice the change when preparing to start the molting process. It is easiest for their eyes to become more opaque and opaque. The color of the shell also becomes grayish, especially in the shade or with a chalky coating.

If your crab has had a previous trauma such as a loss or broken limb, a new cell will also emerge in these places. This new genus will form and grow gradually in an opaque white bag-like part. 

After the molt is complete, this limb will come out but smaller than the original size. However, only after about 2-3 more molts will the parts’ size return to the normal state.


Hermit crab is not a popular pet, so you will have many questions if you own this animal. So we’ll answer some of your frequently asked questions.

What is the perfect base for hermit crab molting?

There is no specific number for a good base layer as it depends on the size of the crab. Smaller crabs only need about 3 inches, while for more giant crabs, you should prepare about 6 inches of substrate. Basically, the whole crab body can be buried in the sand enough for them to carry out their transformation.

How long does it take the Hermit Crab to return to normal?

The molting process of this creature from start to return to normal will take 4 to 8 weeks. More giant crabs may take longer to complete this process.

How should the peeled skin be handled?

If you have separated the molting crab into a private space, leaving its old shell intact. This shell will become a good source of nutrients for them to supplement while rebuilding a new shell, and they cannot walk on their own.

If you keep them in the public environment, you should keep them and pass them on when needed. This crust is rich in calcium and supports the new shell to quickly complete.

how often do hermit crabs molt


Hermit crabs are a natural species, but many people have kept them indoors for many years. Crab has a natural process of development and molting, but you need to pay attention and create the best conditions for them during this time.

This time of molting and regeneration is a sensitive time for hermit crabs, and they are easily damaged if not cared for properly. Hopefully, you have gained more knowledge about this creature with the above article.

Below is an interesting video about how Hermit crab trades their shells

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