Nesting Hermit Crab

[tankwife]

Hi. We have a red hermit crab in our reef tank. We've had it for about a year and we do have a bunch of extra shells for it and it has changed shells twice that we know of. Yesterday it started building what looks like a nest in the substrate in the tank. It did not come out for food yesterday, very unusual. Any thoughts as to what is going on with it? I understand they don't reproduce in captivity, so I'm worried.

 

[Uncle99]

All crabs molt, when they do they are supceptible to predators until the new molt hardens.
Maybe just laying low?

 

[tankwife]

Thank you. Hopefully that is it.