They are protecting themselves from predators when they become soft. They will completely loose their outer shell and shed it and grow a new skin which hardens to a shell. Their exoskeletons are usually found near the molting crab. ... You may need to remove other hermits while they are molting so they are not disturbed.

How long does it take for a hermit crab to molt?

The time it takes for a crab to complete a molt varies. As a general rule, the larger the crab, the longer the whole process will take. It is not unusual for an average-sized crab to spend about four to eight weeks going through the whole process, during which time it may stay completely buried in the sand.

How often do hermit crabs molt?

Most healthy crabs molt at least once every 18 months. SOMETIMES smaller crabs molt more frequently, but not always. So don't worry if it's been a year and your crab hasn't molted yet. Just continue to take good care of it, and the crab will molt when it is time.