HCA: Hermit Crab Association

Title is pretty self explanatory, but around a week ago I moved all my crabs to their new tank except for one. I was digging around in their old tank (I needed to use their old substrate as it had lots of springtails and isopods) and found BigCrab molting and had just shed his exoskeleton. I placed him back under and made a little cave of substrate over him with my hand, then covered him all the way back up (he was maybe 5 inches down).

So, how long does it take for their exoskeleton to harden? Would I be able to relocate him into the new tank by burying him back into the substrate by hand?
I know you’re supposed to let a molting crab lie, but I do need that tank open as soon as possible as I have a crayfish on hold from my local fish store.

I think it mainly depends on the size, usually anywhere from a few days to a week I'd guess. You might be able to move him sooner if you were really gentle but I wouldn't rlly recommend it, it's up to you tho

My biggest worry would be if the 'cave' you made held up as well as his had, or if it has collapsed. I would not have re-buried him when I came accross him. If you decide to dig him up now, be prepared to isolate him from your other crabs.

Update on this: for others asking the same question.
Unfortunately the hermit crab involved in this passed away, I believe Curlysister was correct in saying that the cave likely collapsed. I will make sure to exercise greater caution in the future if I experience something similar.

Can you tell how many times a crab has molted