The Pheasant Tail Nymph remains one of the top mayfly nymph imitations around, and it can be fished in running or still water. It has a distinctive ringneck pheasant tail barb. The gold bead head makes it even more effective by adding weight and fish-attracting color. Per 12. Sizes: 12, 14, 16. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Fly Assortments.