This is a go-to pattern when trout are taking duns on either smooth or rough water. Don’t overdo the number of hackle turns as three wraps will float this fly even on the turbulent parts of a stream.
Hook: Size 16 Partridge Supreme Dry
Thread and rib: Sheer 14/0, claret
Tail: Dark dun cock hackle fibres
Body and thorax: Mole fur
Wing: Tiemco dark dun Aero Dry Wing
Hackle: Dark dun cock
Try this low-riding Mayfly Dun for fussy trout that refuse a high-riding dry-fly.