I first fished this fly in California's famous Davis Lake. There were trout in the 18"-26" range taking this fly with reckless abandon during a particularly heavy hatch one evening. These fish would porpose along the surface of the water and the key to catching them was to time their rise and place your fly ahead of the porposing trout. Was it ever exciting! Use the smaller sizes on most lakes. The Davis Lake Blood Midge is abnormally large.