Dry FliesCDC Biot Dun
The CDC Biot Dun is an excellent dry fly that imitates a range of mayflies in their dun stage. The combination of CDC feathers for the wings and a biot body gives this pattern a realistic silhouette and enticing movement on the water's surface. Its versatility and lifelike appearance make it a must-have in any fly box.
Spring, Summer
Intermediate
Trout
Overview
A refined mayfly dun pattern tied with a quill (biot) body for segmentation and CDC for the wing. The natural taper and upright CDC provide realistic silhouette and soft landings on the water. Typically tied on curved dry fly hooks in olive, tan, or gray tones for matching specific hatches.
Pattern Characteristics
Materials
Hook: Tiemco 100, size #12–#16
Thread: Dun Veevus 14/0
Body: Turkey biot, natural grey
Wing: CDC feather, natural grey
Hackle: Grizzly hackle, sized to match the hook
Tail: Micro fibbets, dun
Fishing Tips
Season
The CDC Biot Dun is most effective in Spring and Summer, during mayfly hatches.
Presentation
Cast the fly upstream and let it drift naturally with the current.
When to Use
Use the CDC Biot Dun when you observe fish feeding on mayflies on the water's surface.
Water Type
This pattern is effective in both moving water and stillwater environments.
Rigging Suggestions
Use a 5X or 6X tippet for a natural presentation.
Visibility & Floatation
The CDC wings and hackle help this fly float high and remain visible on the water's surface. The natural colors also help it blend with the natural insects.
