Why is My Hermit Crab Not Moving?

Pagurus bernhardus Outside Shell

Written by Anthony

I am a content creator by profession but exotic animals are one of my great passions in life. Over the course of my adulthood, I have had the pleasure of looking after stick insects, terrapins, an Egyptian tortoise, giant African land snails, a crested gecko, a Chilean rose tarantula, a couple of curly-haired tarantulas, and a selection of millipedes, centipedes and worms!

Last Updated on March 17, 2021

It is not unusual for a new hermit crab owner to worry about a lack of movement in their pet. While some hermit crabs like to wander about their new tanks, taking in the surroundings and getting a feel for their new home, others prefer to take their time and stay in their shell for as long as possible before venturing out.

However, if you have had your hermit crab for a while and have noticed that it is not moving as much as it used to, you will probably be wondering why. In most cases, molting is the cause of this apparent lifelessness. In fact, many owners believe their crabs to be dead when in fact they are molting.

Is Your Crab Molting?

When hermit crabs molt, they will typically be quite still. It may even be halfway out of its shell. This lifelessness can make it appear as though it is dead, meaning owners often find it difficult to tell whether their pet is alive or not. Nevertheless, if you look very carefully, you may be able to see very slight signs of movement, such as twitches.

It is especially important not to disturb your crab if it is molting. Therefore, if you are unsure then it is best to leave it at this time. If you have just one hermit crab, then you can simply do nothing and leave it alone until you can be sure of whether it is molting or not. If you have more than one crab in a tank though, you will need to take measures to protect it. The best way to do this is to place some plastic around your crab. Cutting the ends off a soda bottle (2-liter bottle should be large enough) and then placing this over the crab will ensure that it is protected from other crabs if it is indeed molting. Be sure to remove the cap so there is ventilation.

The question of whether the crab is molting or dead will quickly become apparent because if it has died then it will start to smell within a few days. If you do not notice an unpleasant smell within a week, it is probably safe to assume that the creature is in fact molting.  

Not all hermit crabs will molt on the surface, which makes it harder to tell if this is what is happening. However, you may notice tracks in the sand, which would indicate that your pet is emerging at night to get food.

But if it has been quite some time since you have seen your crab and you cannot see any signs of activity such as tracks in the sand, you should check by gently moving the sand from around where it is hiding. If it has died in the sand, you will likely notice a rotting smell when you move the sand away.

After your crab has actually molted, you will probably see its exoskeleton on the sand. Many people fear their pet has died when they see this as it looks like a dead crab. Nevertheless, if you look closely, you will see that it is hollow. Your crab has likely found a new shell to hide in, so look about to see if you can find it.

Could Your Crab be Sick?

Molting is not the only reason for a lifeless hermit crab. Although these creatures tend to live long lives, they can occasionally get sick, so it is a good idea to be alert to the signs of illness. Hermit crabs are hardy creatures that rarely get ill. Those that do have probably become affected by mites or problems within the habitat.

As mentioned above, a lack of movement is typically a sign of molting, but it can also be a sign of stress. It can be hard to distinguish between the two so it is important that you can tell if there are any changes in your crab’s behavior. If it is stressed, it might dig down into the sand or hide in its shell more often than usual. One of the biggest indicators of illness is a bad smell coming from the tank. If there are problems within the tank that are making your crab ill, such as mold, mildew, or rotting food, you are likely to be able to smell them before you see them.

If there is a problem in the tank that is causing lifelessness or lethargy in your crab, you will need to deal with it as soon as possible. You will need to remove the crab and clean out the enclosure completely. Clean all furnishings and toys and add some new sand and dechlorinated water.

If you believe that your crab has a mite infestation, there are treatments available. It is probably best to seek the advice of a vet about the right treatments and interventions to use.

Conclusion

In most cases, a hermit crab that appears lifeless is molting and should be left alone. Nevertheless, if you have more than one crab in the tank, you should protect the one that is molting by placing a plastic covering over it.

Occasionally, illness is the cause of lethargy in hermit crabs so if you suspect this is the case, you should try to identify the cause. Speak to your vet for advice if you believe your hermit crab is ill.

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