Kaufmann's Black Stone Nymph works best in well oxygenated rivers and streams. This pattern is a must for trout and steelhead I have had incredible results on many of the Great Lakes Tributaries including the Maitland River Nine Mile and the Bayfield. Time after time the Kaufmann's Black Stonefly Nymph has brought fish to the bank. Your won't fine any serious fly or float steelhead fishermen without an array of Kaufmann's Stone's in their fly tackle box. Kaufmanns Stone Black. Imitates the Salmonfly nymph (Pteronarcys californica) One of my personal favourites. The Kaufmanns Stonefly nymph is one of the most deadly fly and float fishermen patterns. Productive in most rivers and lakes across Canada and the US. I have fished these nymphs in a variety of colours on most of the Great Lakes tribs including the Maitland, Nine Mile and Bayfield. This fly will catch just about every species that swims including Bass & Carp but for Steelhead it is just incredible. The original Black Kaufmanns Stones should be fished close to the bottom so you will loose a few so stock up on these incredible imitations, you just won't regret it.