Dry FliesCDC Biot Thorax Dun

Natural Behavior: Freshly emerged mayfly duns rest on the surface film while their wings dry, riding the current in an upright posture with wings held together vertically. This vulnerable period can last several seconds to minutes depending on weather conditions, during which the newly emerged adult cannot escape predation.

Where Trout Eat It: Trout sip this in spring creek flats and tailwater slicks where freshly emerged duns drift while wings dry.

How to Fish It: Add occasional subtle twitches mimicking struggling duns, presenting with drag-free drift using light tippet during evening hatches.

Best Water: Most productive in spring creek flats with consistent shallow depth, tailwater glides with smooth surface, and back channels.

Strike Type: Trout intercept this low-riding pattern with head-and-tail rises, producing a smooth roll at the surface—set gently as the rise-form completes.

Rigging Suggestions: Use a light tippet to prevent spooking fish in clear water. Apply floatant to the CDC to keep the fly riding high on the water surface.

Seasonal Timing: Use the CDC Biot Thorax Dun during a mayfly hatch. It can be particularly effective in the evening when duns are most active.

Pro Tips: The CDC feathers provide excellent buoyancy and the segmented biot body makes this fly highly visible on the water surface. The natural colors of the materials blend well with the surrounding environment, fooling wary trout into taking a bite.