We are very new to saltwater tanks. We originally got a clown, a blenny, 2 hermits and a peppermint shrimp. The clown died in a week, everything else is still going strong. We then got 2 new clowns (the store said they were paired). One died and the larger of the 2 has a tiny white spot between his eyes. Any ideas? We were told by the store to do a freshwater bath...what is it and do you think it's a good idea?