I have been reefing for 15 years and really havent had too many problems. Right now I have a BIG one. I bought a tang about a month ago and put it in a QT tank. Finally put it in my 90 gal one and my other tangs hated him. I tried to let them fight it out but it got really bad. Finally put him in the overflow for a while. Put him back in main tank and now all my fish are dying. They started getting white stuff all over them and breathing funny. I have read other post but havent been very helpful. Dont know if the tang had something and gave it to my other fish but I took out 5 fish this morning and it looks like more is to follow. I have corals, crabs, shrimp etc in my tank and dont know what to do right now without hurting them. Was going to do a fresh water dip but it is too late for most of them. Also have been feeding them garlic for a while. HELP with a captital H