Sulphur Dun

The Sulphur Dun is a traditional upright-wing dry fly tied to match the Sulphur mayfly (Ephemerella dorothea/invaria) in its freshly emerged adult stage. Its pale yellowish-cream body, upright divided wings, and stiff hackle create a classic mayfly silhouette riding on top of the surface—the unmistakable profile of a dun standing on the water drying its wings before taking flight. Where the Para Dun sits flush in the film, the Sulphur Dun rides higher with a more visible, upright presence that excels in broken water and faster currents where a low-riding fly gets lost.

The Sulphur Dun is the pattern to reach for when the hatch is on and fish are eating confidently off the top in riffles, runs, and choppy seams where the higher-riding profile is both more visible to the angler and a better match for the naturals bouncing along the surface. It's a late spring through early summer staple on Eastern freestone rivers and limestone creeks, producing through the afternoon and evening hours when Sulphur emergences bring trout to the surface. Carry both the Dun and the Para Dun—the fish will tell you which profile they want on any given evening.

Best for:

• Sulphur mayfly hatches from late spring through early summer
  
• Riffles, runs, and broken water where a higher-riding profile is needed
  
• Active surface feeding when trout are taking freshly emerged duns off the top

📌 Pro Tip: Start with the Sulphur Dun in faster, broken water where its upright profile is easier to track, and switch to the Para Dun as you move into slower glides and flats where trout get pickier about a flush-floating silhouette.