Why is my Hermit Crab so inactive?

Originally written by Vanessa Pike-Russell-Updated by Stacy Griffith

Land Hermit crabs are primarily, but not exclusively, nocturnal creatures. That means that in the wild they sleep during the day and are active at night.

One of the reasons why they are inactive when in the wild is that the heat of the day in the tropics where they live would dry them out. Thus, they hide away in the leafy foliage or cool areas and are active once the sun has set and the moon is out, roaming about in groups of 100 or more in search of food.

Other than the heat of the day, hermit crabs avoid predators who will think they are a tasty morsel. If a shadow passes over your hermit crab you will see the instinctual reaction of your hermit crab retreat within their shell for protection. Imagine the shadow of a bird passing overhead, wanting you for dinner , wouldn’t you would retreat into your shell to pretend to be just a shell? I would!

Another reason for inactivity is If the temperature falls below 70F(21C), or the humidity within the crabarium is low. In either of these cases you may find that your crabs are less active. As stated previously in the temperature and humidity caresheets, it is important to keep a comfortable environment for your hermit crabs. 

Sometimes a change in environment can improve the activity of your hermit crabs. If you have a clean area for them to play, such as a plastic container, wire cage or even a plastic washing basket, you will notice that your crabs will spend a long time investigating every inch of it. Another way to increase activity is to create an obstacle course within the tank, using cholla logs or driftwood, coral and/or rocks. Vary the course every week or so and make sure to handle your crabs regularly.

If your hermit crab is inactive for a long period of time which follows the habit of spending a lot of time in the water dish, your crab may be molting. Please read the information in the molting caresheet.