Overview
The Mercury Brassie builds on Gene Lynch's original Brassie pattern with one key modification: the silver-lined glass bead creates a subtle air bubble effect that mimics midges preparing to emerge. Popular color variations include copper, red, chartreuse, green, and black to match different midge species. The simplicity of this three-material pattern makes it quick to tie and extremely durable.
Related patterns
Behavior & presentation
- Natural Behavior
- Ascending pupae hang vertically in the current with gas bubbles trapped beneath their shuck, creating a distinctive profile as they transition toward the surface. Fish key on this mid-column drift stage year-round because the suspended pupae cannot escape and remain available for extended periods.
- Where Trout Eat It
- Trout sip these throughout the water column from 6 inches to 4 feet deep, especially in tail-outs, seams, and along foam lines where drift concentrates.
- How to Fish It
- Dead drift the pattern deep through runs using tight-line contact, allowing natural tumbling motion to match helpless ascending insects.
- Best Water
- Target seams where current speed changes, tail-outs with consistent flow, and foam lines that concentrate emergers.
- Strike Type
- Subtle hesitation or slight tightening of the line signals fish intercepting mid-column drift.
Fishing strategy
- Rigging Suggestions
- Fish on 5X–6X fluorocarbon, 18–24 inches below an indicator or dry fly. Effective droppers include Mercury Pheasant Tails, RS2s, Barr Emergers, and Top Secret Midges in sizes #18–#22.
- Seasonal Timing
- Year round, with peak effectiveness during winter and early spring midge hatches.
- Pro Tips
- The weighted wire body sinks quickly to the feeding zone. The silver-lined bead catches light and creates flash, drawing attention from feeding trout.
Where to fish it
Rivers anglers pair with this fly, with local shops that stock it.
River details and fly shops from River & Run, our sister site.
Entomology
Midge pupae drift suspended in the water column while accumulating gas beneath their pupal casings, maintaining neutral buoyancy as they prepare for emergence. Trout selectively feed on these mid-water pupae during their prolonged pre-emergence drift, capitalizing on year-round availability and the extreme vulnerability of immobile transforming insects.
- Order
- Diptera
- Family
- Chironomidae
- Common name
- Midge
- Organism
- insect
- Life stage
- pupa
Pattern details
- Moving Water
- Rocky Mountain
- dead-drift
- midge-hatch
- classic
- beginner-friendly
- low-clear-water
- tailwater
- spring-creek
