
Emerger · #7 of 129
WD-40
Imitates: Midge or BWO emerger
Quick Reference
- Best Sizes
- #18-22
- Best Season
- Year-round, especially winter
- Best Conditions
- Tailwaters, slow seams, midge hatches
- Water Temp
- Below 55°F
- Recommended Tippet
- 6X fluorocarbon
How to Rig It
Dropper 12" off a Zebra Midge or Pheasant Tail.
How to Present It
Dead-drift just under the surface. Watch for subtle indicator twitches.
Why It Works
Sparse profile in the surface film perfectly imitates a midge struggling to emerge — the easiest meal on a winter river.
History
Mark Engler tied it on the San Juan River. The name is a nod to the lubricant — 'it works on everything.'
Pro Tip
Pair a #20 black WD-40 with a #20 olive WD-40 in winter and let the trout vote.
Frequently Asked Questions
What does WD-40 fly stand for?+
It's a tongue-in-cheek nickname after the lubricant — the original tier joked it works on everything.
Try the Fly Advisor
Not sure if WD-40 is right today?
Get a fly recommendation based on live water temp, flow, sky, and time of day for any river in the US.
Open Fly Advisor