I have attached a photo of what can really only be described as an open wound/sore on one of my gold barbs. Another one has a kind of whitish patch where this ones sore is. They are the only 2 of the 6 barbs to have this affliction. Also none of the other fish seemed to be affected and the 2 with the spot haven't been acting any differently. It's a well established tank and the gold barbs have been in there for about 6 months themselves with no issues. My question is does this look like a disease/fungus someone has seen before? And if so what methods should I take for treating it? Thank you for any and all of your help.