Mercury Midge
Developed by Colorado guide Pat Dorsey, the Mercury Midge uses a clear glass bead instead of a tungsten bead, creating a 'mercury' trapped-air bubble effect that perfectly imitates the ascending pupa carrying a gas bubble beneath the surface. This singular feature makes it devastatingly effective on heavily pressured tailwaters where fish have seen every other midge pattern. Best fished on a dead-drift just sub-surface on 7X tippet.
- Type
- nymph (Midge)
- Hook sizes
- #18–24
- Target species
- trout
- Difficulty
- intermediate
- Best seasons
- spring, fall, winter
Materials
- hook: Scud or curved midge hook #18–24
- thread: Black or white 10/0
- bead: Clear glass or silver-lined glass bead (mercury effect)
- body: Black or white tying thread, smooth
- ribbing: Fine silver wire
- thorax: White or black dubbing
Tying steps
- Slide a small clear glass or silver-lined glass bead onto a size 18–24 hook.
- Tie on black or white thread; wrap a smooth base from behind the bead to the bend.
- Wind a smooth, slim body of black or white thread to the 3/4 mark.
- Tie in fine silver wire and wrap 6–7 tight spirals over the body.
- Apply a tiny ball of white or black dubbing as the thorax just behind the glass bead.
- Whip finish and apply thin UV resin to the thread head behind the bead.
- Apply UV resin over the thread body and cure to create the characteristic mercury-bead effect.
- Inspect the body surface — it should be perfectly smooth and translucent, with the bright silver bead visible through the resin.
- Inspect the cured body at an angle under bright light — the silver bead should be clearly visible as a bright spot through the translucent UV resin shell.