That's a knottyhead, and they will hit nymphs with some regularity. I've only ever caught one on a dry fly. You usually find them lower down in streams, and they were once common in larger rivers (Tuckasegee, French Borad, Little Tennessee) although muskies have worked on them pretty good. Although bony as all get out, they are delicious to eat if you score the back and cook to crispness so the bones soften. They will occasionally reach 10-11 inches in length and when they do the head and gill plates turn a sort of reddish-pink. They also are every bit as sporty, when hooked, as a trout of a comparable size. Just look on them as a sort of Smoky Mountain whitefish.