Want to catch big fish? Then throw on a streamer fly pattern. These are flies which imitate baitfish, leeches and large insects. They act like a regular “lure” for lack of better words. You cover a lot of water with these flies, and activate the predator instincts in a fish, especially trout. Trout are natural predators, and when an big invasive species, like a streamer fly, come into their territory, they’ll strike it down resulting in hopefully your best catch of the day!