Help!!! Hermit Crabs Dead!

[FishmanJosh]

I added 4 red legged hermits into my 20g last night along with 6 turbo snails and 1 emerald crab. My snails and emerald all went off by this morning and are now doing fine, but my hermits did absolutly nothing. I aclimated them all the same nd my water paras are fine. 2 of the hermits moved about a bit but arent doing much, but one of them is just staying inside his shell and I can see his legs but hes very still so possibly dead. Also one of them just crawled out of his shell this morning and died. I will also point out all his colours are still there put I poked him and he is pretty dead. Do hermit crabs molt? Because if thy do it looks like the whole crab and not a carcass. I can post pictures if you like. PLEASE HELP!