The black gnat dry fly is an excellent trout fly to use when any small dark or black insects or the real flies are on the water. Clouds of black gnats can often be seen hovering over the water and it is inevitable that some of these will fall into the water, thus becoming a food source for the trout. Black gnat flies are a delicacy to all trout species. Fish static or on a floating line with a varied retrieve, try it when there does not appear to be a surface action, as it will be the one the trout are looking to see float by.The fly is tied to represent a terrestrial insect rather than one of aquatic origin. There are several different species of the black gnat trout flies and all are taken prolifically by trout year round.