Are my crabs molting or just digging?

[_miranda]

I have three new hermit crabs that have been with me for about a week. How do I tell stress digging from molting digging? Two of the three have dug down, one of which just now came up for air after having been under since I got them, the other having just dug down today. I am very scared of them being eaten by their tankmate: one is in an iso tank, but one is in the main tank with the not digging crabbie. I don’t want to do the wrong thing...help?

[curlysister]

It's hard to say why they are digging. But crabs don't need to be isolated for molting. As long as tank conditions are correct - tank is large enough for the number of crabs, appropriate substrate is at least 6 inches or 3x as deep as the largest crab (whichever is deeper wins) and is moist enough to hold shape, temp and humidity are correct, dechlor fw and msw are available, correct foods are given, enough extra shells are present, etc - they shouldn't eat each other when molting. I have had my two crabs for over 8 years, and the only time there was a problem was when my substrate wasn't deep enough: Sonny dug up Cher and she lost a leg. I corrected the problem, Cher has molted twice and Sonny once since then with no problems.