HCA: Hermit Crab Association

Does anyone know if moonseed would be dangerous? I have a bunch of (I think) wild grape vines in my backyard which I would like to use for my tank, but I've heard that moonseed is very similar.

So, I have a large PP that just finished molting, and I'm seeing some white fuzz on his pincher claw. Is this normal? It looks kind of like mold, but that couldn't be possible, could it? He's very much alive, and I've never heard of mold growing on a live crab. Some fresh food I gave them did start ...