I have caught numerous Trout with either pattern. I believe the Crackleback is a more multi-dimensional pattern, however. The Griffith’s is almost always tied small (18-20) and the body is only peacock (an admittedly great material). The Crackleback can have any colored body with two to three strands of peacock pulled up over the body. Hence, you get a variety of body colors and the effectiveness of the peacock. Also, note the hackle is wrapped to allow more visibility of the body. If the Griffith’s Gnat is supposedly a midge cluster, the Crackleback can also be tied for this clump of midges and also pulled under to represent emergers, etc. The pattern was originally tied (Ed Story~FC Feathercraft of Missouri) as a river/stream pattern fished on the surface, drifting down until it went under and stripped back in darting movements to elicit a strike. Below is a how to link with the ususal extraordinary photo by Hans Weilenmann.