"I fished an Isconychia hatch on the Hiwassee River at Reliance, Tennessee, from a guided drift boat on June 21, 2010. I started using this Knock-Down Dun fly, in a size 14, shortly before noon, after mininal success with a weighted nymph pattern. The Knock-Down Dun resulted in a 20+ fish day -- browns and rainbows. All of the fish took the fly gently in the film, in the corners of their mouths, as though the fly were an emerger. I gave my remaining Knock-Downs to the guide and ordered 20 more when I got home."