Red legged crab shed or dead?

[lil.guppy]

I found my red legged crab without its shell, dead, and where the shell was is this hollow white looking stuff kinda like from the shell of one of my cleaner shrimp.
So did he shed or could one of my fish ripped him out?

 

[uneverno]

Are you talking about a hermit crab?
If so, I'll find my cleaner shrimp dragging the molt around afterwards, picking out any leftover tasty bits.
My experience with the crabs themselves is that they'll hide for a few days after a molt while their new shell hardens up, and if he molted, it's very possible he also moved into a new house (assuming you have them available.)
If it's another type of crab, IDK.