Over the last couple weeks my blue tang which I've had for over 4 years started developing a while patch on its side. This patch has gotten a lot larger and one has developed on its other side as well. It is still eating and swimming but is not not look healthy and I think it is getting worse faster. I have been searching the web to try to identify what this is and if it can be treated (I have a reef tank, and very hard to set up a quarantine). All my other fish in my tank look great with no signs of stress. Any help would be greatly appreciated!!! I hope the pic attached helps.