Hermit Crabs: Care for Molting

A hermit crab – What is it?

Unlike what the name hints at, a hermit crab is not a true crab. It is a type of crab that does not have a very hard shell and uses the shells of other animals for protection. These smaller shells are discarded for larger ones as the hermit crab grows in size.

There are about 500 different species of hermit crabs found around the world. Most of them live on the ocean floor but some of them live on land too.

Hermit crabs do not have a backbone and instead possess an exoskeleton (an outer shell that provides support for their body but does not provide much protection from predators). Hermit crabs have ten jointed legs, a flattened sensory antenna, two eyes located at the end of the stalk and a soft, twisted abdomen.

What is molting?

Molting is a natural process of growing for a hermit crab wherein it sheds its exoskeleton and forms a new one. The frequency at which a crab molts depends on the growth rate and size of individual crabs with smaller ones molting every 3 to 4 months and larger ones molting once every year. This is a time that the hermit crab needs to be treated with extra care as it is defenseless and vulnerable.

How do I know when my hermit crab is ready to molt?

It is important to always be prepared for molting as some hermit crabs may surprise you when you least expect you. Here are the signs that indicate that your hermit crab is ready for molting.

• Decrease in the level of activity, though it may seem restless.
• Its body will take on an ashy color.
• Antennas look tangled and it shows less activity.
• The eyestalks may face away from each other taking on a V shape instead of being parallel.
• The tips and legs of the hermit crab may turn whitish.
• It spends more of its time underwater.
• Its claws and legs may seem weak or droopy.
• A molt sac(one that stores water to help break the exoskeleton) develops just under the abdomen.
• Its eyes turn whitish and cloudy.
• The hermit crab eats and drinks more than usual for a bit before the molt, this decreases in the last few days before a crab begins to molt.
• It starts digging more than usual.
• Hermit crabs that have a missing limb begin to restore their limbs by beginning to grow a gel limb.

How do I care for my hermit crab when it is molting?

The first thing to keep in mind is that when a hermit crab is molting let it stay where it is. This process may take anywhere from 4 to 8 weeks for an average sized crab; with smaller crabs taking a shorter time and larger crabs taking longer. This is a time when the molting crab is in danger from other crabs. To keep the molting crab safe it is of vital importance to keep the molting crab in an isolation tank.

What are the factors to be kept in mind when I set up an isolation tank?

Since this is a stage when the hermit crab is inactive, a glass tank or small plastic tank will also serve the purpose. Once that has been selected, line the tank with a deep layer of sand and provide chlorinated water as well as salt water in it. Also ensure that some calcium rich foods such as calci-sand, cuttlebone and boiled eggshells are available. A hiding spot as well as few larger shells should also be provided.

There is a factor that is very important and that is to make sure that the humidity and temperature are right, to do this you might have to invest in a humidity gauge and a small heating pad as well. Temperatures on the high-end are recommended for molting crabs as also proper humidity, as moisture is critical to the molting process.

How long should I wait before returning the hermit crab into the main tank after molting?

It is advisable to wait until the crab is moving around as well as drinking and eating normally. This should take a few days to a couple of weeks.

Once the new exoskeleton has hardened and you would like to return the hermit crab into the main tank, you could give it a lukewarm dechlorinated bath!

What do I do with the molted exoskeleton?

As the exoskeleton is a rich source of calcium, it is needed by the crab to grow a healthy new exoskeleton. A crab that has just molted will usually munch on the molted exoskeleton for a few days after it molts. You can move the uneaten bits of exoskeleton into the main tank once the crab has begun moving about.

The uneaten bits (which consist of the parts that are too hard to eat) of exoskeleton can be removed after a few weeks.