I think one of my crabs may be molting. He needs it, he had rounded off leg tips and what-not. But my question is how long he should be under? What is the average molt time for a crab his size? He has been under for 7 days, I don't know if he is dead or not. I recently added salt water because I remembered to buy distilled water finally. The salt that I have is API aquarium salt, when I put it in they seemed to love it. I looked it up and i didn't find anything bad about it. After I put it in he filled up on it and food and went under. I almost forgot his size is if I had to explain it would be the size of 2 quarters, like if you melted down 2 quarters and then smashed it out to the thickness of 1 quarter, but the area of 2, that is how big I would say he is, shell included.