It’s often difficult to tell whether a hermit crab is dead or molting, so even experienced owners can have trouble determining the difference. Hermit crabs usually show signs of getting ready to molt, but these signs are often missed.
However, once the process has started, you can look for things that’ll tell you that the molting process is in progress and that the hermit crab isn’t dead.
Unfortunately, sometimes hermit crabs die, which can occur during the molting process. Determining whether a hermit crab is dead or just molting sometimes involves playing a waiting game.
Until you’re certain that a hermit crab is dead, you should avoid touching it. Disturbing a hermit crab while it’s molting can disrupt the process and kill a hermit crab.
Hermit Crab Molting Process
Hermit crabs need to shed their exoskeleton as they grow. The molting process involves them shedding their exoskeleton, which is a hardened skin that protects their soft flesh.
After they shed their exoskeleton, hermit crabs can’t move for some time while they regain muscle control, and their new exoskeleton hardens.
According to Marine Invertebrates of Bermuda, hermit crabs often eat their old exoskeleton to supply their new exoskeleton with calcium. Calcium strengthens the exoskeleton the same way that it strengthens human nails, teeth, and bones.
During molting, hermit crabs can regenerate limbs lost due to injury. Molting aids in the hermit crab’s growth and is also a healing mechanism.
Stages of Molting
There are four stages of the molting process:
Stage 1: Pre-Molt
This happens before the molt occurs when you may notice signs of the impending molt.
Buds will form where limbs used to be in preparation for regeneration during the molt. Hermit crabs will begin to store water and food and may stop eating right before molting.
Stage 2: Molt
This is the shortest stage, occurring when hermit crabs shed their exoskeleton. During this time, hermit crabs become immobile due to a loss of muscle control.
Terrestrial or land hermit crabs remain in their shells during this stage of the molt to protect themselves while their soft flesh is exposed.
Stage 3: Post-Molt
The new exoskeleton starts to harden, and the hermit crabs begin to regain muscle control. It’s at this point that hermit crabs will usually eat their old exoskeleton.
Stage 4: Intermolt
During this period, the exoskeleton gets stronger and harder. This is the period between molts, which is known as the period of rest.
The length of time this stage lasts varies but tends to get longer as the hermit crabs grow larger. Adult hermit crabs usually molt less often than young hermit crabs.
Signs Hermit Crabs Will Soon Molt
There are signs you can look for that will give you a clue that molting is about to begin soon.
However, since hermit crabs may do these things at night when most active, you may not see the signs before molting happens.
Hermit crabs contain a molt sac on their abdomen, which stores the water they drink and helps break open the exoskeleton when molting begins.
Your hermit crab may stop eating in the days following the molt. Those who notice that the hermit crab has stopped eating sometimes mistake their lack of appetite as a sign of illness.
If you’ve noticed other pre-molt signs, you’ll recognize this is normal because molting is about to start and not because your hermit crab is sick.
If a hermit crab is usually pretty active, you may notice a sudden decrease in activity. Your hermit crab may also start digging excessively or changing shells more often than usual.
Change in Appearance
You may notice a change in your hermit crab’s coloring. Its body may take on an ashy or dull coloring, and its claws and legs may change to a whitish coloring.
Their legs and claws may look droopy, and their eye stalks may turn away from each other and resemble the letter “V.”
Missing Limbs Begin to Regenerate
If a hermit crab is missing a limb, you may begin to see small buds appear where those limbs used to be in the days leading up to a molt. During the molting process, those limbs will regrow.
Do Hermit Crabs Look Dead When They Molt?
Hermit crabs are often mistaken as being dead when molting. During the second phase of the molting process, hermit crabs can’t move, and their bodies come partway out of their shells.
If you’re unsure whether your hermit crab is dead or just molting, leave it be and watch for signs that will tell you if it has died.
Signs a Hermit Crab is Dead
If you think your hermit crab might be dead, the best thing to do is wait in case it’s just molting. During the waiting period, look for signs that will tell you whether a hermit crab is dead or not.
Take a whiff of the air inside your hermit’s tank. The hermit crab is likely dead if you smell a rotten or fishy smell. However, sometimes molting hermit crabs can also give off an unpleasant smell, so look for other signs of death.
If you’ve waited a month or two because you were unsure if your hermit crab was molting or dead, check to see if there are any signs of mold growing on it. Evidence of mold indicates you have a dead hermit crab in your tank, and you’ll need to dispose of it.
However, hermit crabs that are alive can sometimes develop mold spots for different reasons, such as the humidity level in the tank being off or there’s a fungus or bacteria in the tank.
If your hermit crab is covered in mold, it’s dead. If it only has a spot or two of mold, continue waiting and watch for other signs.
Stiff and Falling Apart
Usually, when an animal dies, it’ll become stiff and eventually will start to decompose and fall apart. If you notice that a hermit crab has lost parts of its body in one area, it’s probably decomposing.
Keep in mind that when hermit crabs are molting, they’ll shed their exoskeleton, which sometimes people see and think it’s a dead hermit crab.
If what you’re seeing looks like a shed exoskeleton, the chances are your hermit crab is hidden in a shell going through the molting process.
What Does a Molting Hermit Crab Look Like?
Since the molting process has different stages, your hermit crab will look different depending on where it’s at in the process.
You’ll likely only be able to see what your molting hermit crab looks like if it’s molting on the surface. Most hermit crabs bury themselves in the sand or bedding to molt.
If you can see your hermit crab, you may notice that it looks motionless and limp, almost as if it’s dead. That’s why many people have difficulty determining whether their hermit crab is dead or molting.
Out of Shell
It’s normal for hermit crabs to come part way out of their shells during the molting process. Not all hermit crabs will do this.
If you noticed pre-molt that your hermit crab’s color had changed and became dull and ashy, you might see that its normal color has returned during molting.
What to Do When Hermit Crabs Molt
If a hermit crab is in a tank alone, you don’t have to do anything while the molting process happens. Keep an eye on it to ensure it hasn’t died during the process.
If a hermit crab is housed with other hermit crabs, keep a closer eye on the molting hermit crab to ensure the others are not harming it. This is less of a worry if your hermit crab has buried itself to molt.
A hermit crab that has chosen to molt on the surface and is housed with friends is in danger of being disturbed or harmed by the others while it molts. To keep it safe, you can cut a 2-liter soda bottle in half and turn it upside down around the hermit, enclosing it safely.
Otherwise, just ensuring that the tank stays at the proper temperature and humidity, there’s not much else to do for the molting hermit crab until the process is complete.
How Long Does It Take for a Hermit Crab to Molt?
The time it takes for hermit crabs to molt varies depending on the size and health of each hermit crab; this usually ranges from a few weeks to a few months. Typically, the smaller the hermit crab, the less time it takes to molt, and the larger the hermit crab, the longer it’ll take to molt.
There’s no set-in-stone, clear-cut answer to this question because sometimes small hermit crabs take much longer to molt than a large hermit crab. So many factors are at play that no one can predict or even provide a good guesstimate on how long an individual hermit crab will take to molt.
However, if you were to follow the typical timespans, tiny hermit crabs can get through the molting cycle in as little as a week. They may stay hidden for up to four weeks as they allow their exoskeleton to finish hardening or until they feel safe coming up to the surface again.
Some hermit crabs stay hidden under the surface for weeks after the molting process has completed, only coming up occasionally to eat and drink and then disappearing again.
How Often Do Hermit Crabs Molt?
Adult hermit crabs tend to molt every 18 months, while younger hermit crabs molt more often. However, there isn’t a set number of times hermit crabs can molt during their lifespans.
Some factors can make molting occur more often, such as shell size. The New Zealand Journal of Marine and Freshwater Research stated that hermit crab shells that are too small or too heavy restrict growth and can cause more frequent molts.
It goes on to say that when hermit crabs are limited in their choice of shells, they must choose whatever shell they can find. Sometimes those shells are too small.
Living with other hermit crabs can allow them to trade shells with another that might be more suitable in size for them, but this isn’t always an option.
When they can’t find a larger shell, their growth becomes restricted by the smaller shell, so they molt. After the molting process is completed, sometimes hermit crabs are smaller than they were before the molt, so they can fit into the shell they have.
Annual Reviews confirm these claims and even go as far as to say that hermit crabs kept in captivity molt less frequently than those living in the wild.
Based on this information, it might be wise to put empty shells of different sizes in your hermit crab’s tank. Giving your hermit crab shell choices will ensure that it never has to worry about size restriction after a molt due to the inadequate size of its shell.
Providing extra shells for your hermit crabs will also limit the number of shell fights your hermit crabs get into because there aren’t enough shells to go around.