Pheasant Tail nymph
The Pheasant Tail nymph (PTN) is probably the fly that catches the most trout overall. A general imitation often fished dead drift or using the induced take method. Fish it like a dry fly in the surface if you have problems with fish not taking dry flies as it imitates a large variety of nymphs living in rivers and lakes. It has certainly survived the test of time being invented by Frank Sawyer.