i lost 2 shrimp in the past two weeks thinking they were molting. one died 2 weeks ago and i thought he was molting because i saw what i thought to be an exoskeleton but it was the shrimp. then in a week the other cleaner shrimp disappeared and the next day i saw him floating around. i picked him up and broke him and he was hollow so i thought it was an exoskeleton but havent seen him since. i have a small 3 stripe and a blue damsel in a 75 with live rock and other inverts like hermits and snails. all tests are good and i dont have an iodine test though. is there anything that could cause this because i think it may be the iodine. they were in there for 2-3 weeks.