I've been attacked several times by cottonmouths while fishing. I usually carry my stringer of fish with my while wade fishing through rivers and lakes, and on several occasions I found some sort of water snake trying to eat my fish. The first two times I just scared the snake away. But the next couple times, I put a large minnow/shad onto my gear and actually fished the snake. I landed them both, and both were quickly beheaded.