While fly fishing in some high alpine lakes, I ran into a weird fish! It looks like a brook trout with external gills! This fish was living under a rock near the bank, which surprised me. I have never seen this before and I assume it is some kind of mutation due to low oxygenated water? Anyone out there a fish biologist and can lend some more information? At first I thought is may have been a deformity or abuse from an angler, but the gills are way too symmetrical I think for that to be the case.