I recently bought a Powder Blue tang, on Saturday. When I put him in he was fine for the 2 days but today I just got home and he is upright against a rock, flapping his fins, and opening and closing his mouth, not moving!... please help! The tank is a 50 gallon salt water tank with a PH or 8.2, tank mates consist of, Blue tang, Yellow Tang, 2 Malanopis Clowns, pygmy angel fish and a cardinal fish. The only chemical iv added was 2 days before I got him and it was to raise Calcium, and Alkalinity, It was a Kent Marine's Product