Hello everyone! I have a 3 gallon tank with 4 hermit crabs and this happens about 2 times a month but with different crabs. Ill wake up or come back from work and one of the shells will be empty and ill see what appears to be half a dead hermit crab on the bottom of the tank. The first time this happened i thought the crab had died. But to my amazement the next morning the crab would be back in the shell as if nothing had happened. Is this some kind of molting or shedding of the skin? Really interested to your answers?