Subvaria nymphs prefer riffles with fast to medium current, and begin to become active as the water temperature reaches the 50 degree mark. They swim to the surface, this swimming motion make them an easy target for hungry fish. Fishing a subvaria nymph imitation suspended in the water can poroduce well both before and during the hatch. Upon reaching the surface these nymphs lay suspended in the film while emerging from their husk, this makes emergers an easy target for feeding trout. Duns ride on the surface for a good length of time in the cool early season providing good dry fly fishing. When the evening air temperature warms up, 65 to 70 degrees suibvaria spinners begin to show up in great numbers providing some of the seasons best spinner falls.