What could've caused this? I have some corkwood in the tank for him to climb on. I added a little ceramic hut for him to hide in. I fed him. His claw just suddenly fell off and then two legs! Then I found him dead. I added some salt to the tank because I read that they like this. I even have a little filter running for him. It could've been trace amounts of melafix that killed it, but I washed out the tank and gravel before I added him. I don't know why it died and I would like to get another to replace it, so I was wondering if anyone could help me out by telling me exactly what I need to do to take care of them. It was in it's own little 2.5 gallon tank, not in the big tanks just so you guys know.