This is a popular fly pattern, designed to travel below the surface of the water after it has been cast. I don’t use a fly rod but a casting rod, instead. If I were to use this lure, I would attach a clear casting bubble stopped by a sinker ahead of about two feet of 6 pound test line to which the fly is tied. The bubble can be filled with water to add ballast, thus distance when casting into a lake or river. The lure will be slowly retrieved, then cast out again til the hapless trout spots and bites it.