HCA: Hermit Crab Association

I have three Hermit Crabs in a 10 gallon tank. They are relatively small, I think...all their shells are considerably smaller than ping pong balls. Anyway, I've had one since February [a late Christmas gift] [Napoleon] and got the two [Sisyphus and Persephone] others within a month or two after reading they need friends. In the middle of April, I added more sand to their crabitat, after reading that it needed to be higher than I had it. Within a week both Napoleon and Sisyphus dug in [presumably to molt; they were big for their shells when I got them] and I haven't seen them since. Persephone hides for a couple of days at a time [her shell is much bigger than she is, so I assume she doesn't need to molt yet] but has started chirping more, too. Since her crabbie friends have been hidden for so long, and they're social animals, should I get another crabbie friend for her while the other two are underground? Also, I'm not worried about the two hidden ones, but should I be?

I wouldn't worry about your girl being lonely she will be fine until the other two re-surface, its not recommended adding in more hermitcrabs on top of relatively new purchases as each hermitcrab needs a four week isolation period to de-stress and molt if need be so purchasing another new crab would likely result in that crab also burrowing down in a couple of days leaving the lone girl in the same situation.The two that are buried haven't really been down long enough to start worrying at this point give them a few more weeks as they can be down for up to two months at a time under certain circumstances so this is not unusual at all.

Crabby paddy is all by himself now while the one upstairs molar. I went through that oh he is lonely phase to..I ended up with 5 crabs in like 2 months before I said no more..they are just going to have to tough it out !