Dry fly
Blue Winged Olive
Mayfly generic imitation
Trout · GraylingSurface
Olive-grey body, white or pale wings — the go-to pattern when small dark olive mayflies are hatching. Simple, effective, and effective because it doesn't overthink the problem.
Fish this when
Spring and autumn when Baetis or iron blue mayflies are emerging. Upstream and dry-fly fishing when you see small olives on the water.
Why it works
The hatch is obvious, the fly is obvious. Olive-grey body, pale wings — trout see it and take it. Simplicity works.
Naturals it imitates
blue-winged olive; olive dun; small upwing adult
Typical zone & fishable range
usually
Surface
Film
Subsurface
Deep
Setup sensitivity: medium
Buy or tie?
Blue Wing Olive
Smitty's Monthly Fly Box · canonical
A1 Trout Flies
Good UK stillwater source for FABs, lures, buzzers, blobs, boobies and modern reservoir patterns.
Stillwater Fisheries
UK stillwater-focused fallback for trout flies and stillwater tackle.
Flies Of Ireland
Dedicated Irish lough-fly specialist; sells this pattern under its exact name.