Hello. So I have phito crabs and am new to having any kind of crabs. I found a empty shell in their tank today and it kinda shocked me lol. I'm hoping it molted??? Is that what you call it in crabs? If so how ofter does this happen? At what age does it start? Will the other phito crabs hurt it now? Is their new shell soft? I have so many questions, sorry. I just want the best for them. Thank you xo