Just the past week I have lost 7 of my fish over the course of 3 days with the exception of my 2 "Blue Chromis". I don't know what happened. The last fish to die was my clown. Several weeks ago I added a new rock to the tank "thinking it was fully cured".. Not sure but I also noticed like a white film and my clown fish right before he died, and a couple white dots on my angel and tang before they died. I tried moving some fish to my quarauntine..it all happen to fast. The Chromis don't have any apparent spots on them and seem to be fine. Any clue on what to do now. I don't want to add anything else without knowing what was wrong. Please help!!