I'm curious on digging or molting crabs???

[Travis91]

My family purchased 3 hermit crabs while on vacation in Florida. Had them right at a month now. They are purple pinchers and we didn't know what all went in to caring for them and how badly they are treated but we said alright we bought them and going to give them the best life/ chance possible. We bought a 37 gallon tank. Did the pps system in the tank. Just added more substrate a 5 to 1 mix of play sand and eco earth at 9 inches. They have climbing stuff, a wheel, fresh and salt water they Can submerge in, the two UTH keep the tank on average 78 degrees (shooting for 80) and my RH is around 87% average. They get a new food item every night a vegetarian or fruit and protein from eggs, sardine, river shrimp, worm castings and cuttlefish bone always available. They are active at night we keep a camera on them and watch them. Took us forever and multiple orders to finally find the right type and size shells but yesterday got the right ones. Last night memory on Cam filled up and quit recording all three active like always. I can't find one now. I've turned over all my shells. I could be wrong but I'm 90% sure all the shells are on the surface. But I could be wrong on that. I've tried counting on the camera but there is more in the tank than in that so that's out. I see no tunnels though the one missing (crabby) because he's the crabby one picking on the other two (non violent) is the digger not the other two. Is there always a tunnel after burying for a molt? I know they dig to relieve stress but do they completely bury themselves just below the surface with no trace? I know all three are ready for the first molt with us so I don't want to disturb the substrate in the chance he is molting. He has every sign of getting ready to molt besides lethargy. He's escape once out of one of the two lid vents you can open or close but I fixed a plastic mesh over both so I don't think he made it out again. Sorry for the long story and info but figured it could answer alot of questions people will ask. Thank you in advance.

[Travis91]

Ok found him he's buried. I submitted a picture he's not very deep. 2 inches tops. I don't know if he is in a shell. Should I gently move the substrate and check? Wait it out? I'm invested in these little guys making it so please help.

[JTKermie]

I would wait it out unless you are 100% sure the crab is out of his shell and what you see isn't an exoskeleton with the crab near it, inside his shell. I think there's another recent thread on the same situation.

If for sure you have a shell-less crab, I'd follow the emergency procedure to get him/her to reshell asap.

[Travis91]

So his tunnel I guess you'd call it feel in and there's a chamber around him. He is in his shell moving a little bit no exo Skelton yet keeping a close eye to make sure he don't start molting an inch below the surface. I'm thinking he just did it for stress relief. Thank you for your reply.

[JTKermie]

I think you're on the right path. See how he does. Maybe he dug to a point he feels safe enough to molt.

[curlysister]

Crabs will back-fill the tunnels that they dig - this protects them from a predator (or another crab) following them down the tunnel. You generally will not know where they are underground - they often move around once they are under. And you won't know if they are molting, or de-stressing, or just digging for fun. This drives us all crazy - we want to know where they are/ what they are doing/ if they are okay. But we can not. It is important to leave them alone once they have gone underground - don't dig for them or poke around trying to find them. As long as your substrate is deep enough ( at least three times as deep as your largest crab), and is sand castle consistency (so their tunnels and caves hold their shape), and the tank is not over crowded (otherwise they can accidentally come across each other when digging underground)....then we just need to trust that they know what they are doing down there.