HCA: Hermit Crab Association

So I just purchased my first two crabs. One I bought dead (teaches me to inspect them better) and the other was very active at the pet store and as soon as I brought him home he ran around for a bit then slowed down. This morning he is near the back of the tank in a shallow hole. Does that mean he's getting ready to molt? Or just possibly destressing?

Could be destressing, but from my experience when I bring crabs home from the pet store mine never seem to dig until they're ready to molt. They're usually exploring the tank, power eat for 3-7 days then dig down. Does your crab have hairy legs and black nails? If not it's probably preparing to molt.