HCA: Hermit Crab Association

I bought a 3d-printed climber for my crabs. It says it’s made of PLA. Some people have said that it’s safe, and some said it’s dangerous. I want to check before I put it in my tank.

I have 3 hermits, and I’m a new owner. (Less than a year of hermit keeping.) All three went down at different times in mid-July. The other two came up for about a month, then went back down. But my third crab, shes the biggest out of them; maybe an inch?, hasn’t come up at all. I’m worried that she’...