I agree with you Terry, but one thing is trying to get the fish out of the tank. Granted the sailfin should be pretty easy to get out, but smaller fishes like dwarf angels are tough. You'll have to tear the whole tank apart. I have over 200lbs of LR in my tank and there's no way I'll be able to get my coral beauty out. Cleaners shrimps help rid the disease and garlic help prevents it, but you have to look at what's causing it; lack of foods/vitamins, aggresiveness from other inhabitants, poor water quality or just a bad specimen. I have a sailfin myself for over a year and I've seen this fish go through hell and back where most others didn't make it. They're one of the hardier tangs out there. Komet, what are you feeding it, other fishes, water quality?