Flesh Fly - Streamer. The Flesh Fly should never be forgotten during salmon runs, when salmon begin spawning and soon after begin dying the nearby rainbow trout and other fish that feed on the salmon spawn also devour the flesh of the dead salmon. This is where the Flesh Fly comes into play, imitating floating flesh from the dead salmon the trout simply cannot resist this hefty piece. As odd as this method may sound it has proven time and time again that it works especially in Alaska with their huge salmon runs, this fly is most effective from late summer until winter freeze.