Trico Dun
The Trico Dun matches the freshly-emerged adult before it transforms to a spinner. The dun emerges early in the morning in July through September, and while the spinner fall often gets more attention, selective fish sometimes key on the dun phase during the emergence window. Use a parachute or CDC pattern in tiny sizes (#22–26) with 7X tippet on smooth morning water. Patience and precision are required — the fish are often sipping rises that are nearly invisible.
- Type
- dry fly (Mayfly)
- Hook sizes
- #22–26
- Target species
- trout
- Difficulty
- advanced
- Best seasons
- summer, fall
Materials
- hook: Dry fly hook #22–26
- thread: Black 12/0
- tail: White Microfibbets, split
- body: Black tying thread
- wing: Small CDC feather, upright
- thorax: White or cream dubbing
Tying steps
- Mount a size 22–26 hook; start 12/0 black thread.
- Tie in 3–4 white Microfibbets as a split tail.
- Wind a body of black or olive-black thread from bend to the 3/4 mark.
- Tie in a tiny CDC feather as an upright wing stub.
- Dub a tiny white or olive thorax ahead of the wing.
- Whip finish with 3 careful wraps; apply UV resin needle-thin.
- Apply no head cement near the CDC post; a bare thread head with a 4-turn whip finish is sufficient.
- Inspect the body segmentation from the side — the alternating dark thread wraps should be barely visible as subtle ribbing.
- Hold the finished fly at arm's length — the tiny white CDC post should be clearly visible against a dark background, confirming adequate height for visibility.