HCA: Hermit Crab Association

My first molter dug in yesterday. I had just replaced their sand substrate with perfectly mixed sand and fiber - texture was sandcastle perfect! So, now how do I make sure the sand tunnel he's in doesn't collapse?

As long as it was moist before he went down he should be just fine.

Keep the top layer moist by misting it when needed, but you shouldn't have to really do anything (other than be patient and wait for him to surface again).