This pattern addresses a common, and invariably frustrating, fishing situation-trout that refuse everything in your fly box while delicately dimpling the surface as they take something too small to see. It could be little ants, or tiny mayflies, or microcaddis, or midges. But it doesn't really matter. Often enough in trout fishing, fly size is far more important than color, shape, or pattern. When trout are sipping the small stuff, a little Griffith's Gnat usually turns the trick. It is also a good change-of-pace pattern for any rising fish that refuses your best efforts; sometimes just going small makes the difference.