My fiddler crab has turned a darker color and in the last 24 hours has lost his large claw and a leg. He is very still and keeps moving his legs oddly when he does move. Last night he was picking at his large claw and I found it at the bottom this morning. Now he's been sitting on top of a rock out of the water and one of his legs popped off and he was bubbling from the mouth a bit. Is this molting? I'm semi new to fiddlers. I've had him in my new crabitat for about 2 weeks now (was in a fresh water aquarium before). There's plenty of space to get out of the water and the water is brakish between .006 and .0012. Temp is about 75. I introduced a female about 3 days ago. Try don't seen to bother each other at All and she was nowhere near when the limbs fell off. She seems to be doing fine.