Ok I read that hermit crabs have black nails after a molt. I know none of my crabs had them when I bought them. I know no one has molted yet..but I noticed some all of a sudden have some nails. So can they grow them w/o the molt? My one crab in a painted shell keeps trimming the opening of his shell. Is this normal? He was shell shopping one day and I know he wanted to switch but just seemed stuck. Could his abdomin be stuck? He does not appear to be stuck other wise. This is the second time I have found him on his side trimming his shell.