I was fly fishing in Little Campbell Creek Monday evening (felt like escaping the combat zones for an evening) and caught a very nice sized rainbow about 16" long. Fought well, seemed well fed, but the fish's scales on both sides were raised up, giving the trout a very rough texture. The sides were also covered in a foamy looking mucus. Otherwise the fish seemed fine, no discoloration, no visible wounds or sores. It really seemed like the fish had just had its scales rubbed the wrong direction. I tried Googling this and came up with nothing.
Has anybody else seen this before and do you know what causes it?