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

1. Slide a small clear glass or silver-lined glass bead onto a size 18–24 hook.
2. Tie on black or white thread; wrap a smooth base from behind the bead to the bend.
3. Wind a smooth, slim body of black or white thread to the 3/4 mark.
4. Tie in fine silver wire and wrap 6–7 tight spirals over the body.
5. Apply a tiny ball of white or black dubbing as the thorax just behind the glass bead.
6. Whip finish and apply thin UV resin to the thread head behind the bead.
7. Apply UV resin over the thread body and cure to create the characteristic mercury-bead effect.
8. Inspect the body surface — it should be perfectly smooth and translucent, with the bright silver bead visible through the resin.
9. 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.