It's a little duckling fly but it will work on a wide variety of big fish from bass to Golden Dorado. Baby ducks often fall prey to predatory fish like bass and pike or musky as well. This is a great top water / popping fly to attract attention. RIO's Duck Norris gurgles and moves its soft feathers in a way that brings the fish to the surface. The #4/0 hook brings the fish to your hand.