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