Electric blue hermits

Hello to all my fellow SWF friends,
I recently have purchased two electric blue hermit crabs. They acclimated fine and came out for a little bit and then just sat in one spot for three days now. They are three times as big as all the other hermits in my tank so is it normal for them to be so lazy or inactive?
 
They don't even budge when there is food in the tank?
The only time I get them to budge is when I move them. If I pick them up they come out. I set them down they move a little. They are the only ones that do this out of the fourteen I have. Twelve I have are small and very active and they are big and don't do anything.
 
Too late. I got home from work today to find them both dead. Well one outside his shell dead and the other M.I.A. His shell was there but he was gone. :(
My first loss of life in my tank. Makes me sad.
 
Top