Any hermit crab keepers around? Want to ask some questions:

I usually leave them in my room, no open window, but open door to let air in a bit, at night time I on about 1-2 hour of aircond then turn off and switch to fan, would that be a big no no for the crabs? Cause I heard my friend said it before but not sure of it.



Here's mine The one on the left is call Eugene Krab, and the one on the right is call Krab Junior

Awwww man one of my crab died It froze while half of it's body is out and now it won't respond to me when I touch him, usually he would go back inside his shell, but now it doesn't move at all, I'm being hopeful but is it sick?