Dry FliesGrillos's User Friendly
Grillos's User Friendly is an innovative mayfly pattern designed by Anthony Grillo that combines proven materials in a uniquely effective configuration. This versatile dry fly features a foam back for unsinkable floatation, a purple dubbing body that fish find irresistible, and a smoke macrame yarn wing that provides excellent visibility. The white rubber legs add subtle movement while the grizzly hackle ensures proper flotation and a realistic footprint on the water.
Spring, Summer, Fall
Intermediate
Trout
Dec 2025
Overview
This Charlie Craven pattern from Charlie's Fly Box showcases Anthony Grillo's creative approach to mayfly imitations. The User Friendly combines foam-backed durability with the fish-catching appeal of purple dubbing - a color that has proven effective on selective trout. The foam back ensures the fly floats indefinitely even after multiple fish, while the macrame yarn wing provides the angler with excellent visibility without appearing unnatural to the fish. The grizzly hackle and white rubber legs complete the buggy profile.
Materials
Hook: Umpqua XC110BL-BN, #12-16
Thread: Veevus 14/0, black
Tail: Mayfly Tails, tan or dun
Body: Antron Dubbing, purple
Back: Razor Foam, 1mm black
Wing: Macrame Yarn, smoke
Hackle: Rooster Cape (or Saddle), grizzly
Thorax: Ice Dub (or Antron Dubbing), purple
Legs: Fine Round Rubber Legs, white
Behavior & Presentation
Natural Behavior: Small Baetis mayflies emerge during overcast weather in dense congregations, each dun perching upright on the surface with wings gradually expanding. The olive-bodied adults remain vulnerable for 10-20 seconds per emergence, their dark wing silhouettes contrasting with pale bodies as they prepare for flight from predictable current lanes where emergence concentrates.
Where Trout Eat It: Trout strike this during BWO and PMD hatches in both slick water and turbulent freestone runs.
How to Fish It: Dead drift on 4X-5X tippet. The foam back needs no floatant and supports substantial dropper weight.
Best Water: Fast riffles and slick flats where buoyant foam keeps fly floating through varied currents.
Strike Type: Selective risers sip with metronomic rhythm—watch for repeating rise rings in the same feeding lane as fish establish predictable timing, then set gently with a lifted rod tip when you see the take.
Fishing Strategy
Rigging Suggestions: Fish on a 9-foot leader tapering to 4X-5X tippet. The buoyant foam construction makes this an excellent indicator fly in dry-dropper rigs.
Seasonal Timing: through fall mayfly hatches, particularly during BWO and PMD emergences when the purple coloration seems to trigger more strikes than natural-colored patterns.
Pro Tips: Adjust presentation depth and speed based on fish activity level and current conditions for best results.
Entomology
Small mayfly duns emerge in dense numbers during predictable hatch windows, riding the surface film with upright wings while completing final wing expansion. Blue-winged olive species often hatch during overcast or inclement weather when lower light levels increase their vulnerability period. Their consistent size and profile allow fish to establish selective feeding rhythms, methodically rising to intercept duns in preferred current lanes where emergence concentrates.
- Order
- Ephemeroptera
- Family
- Baetidae
- Common Name
- Blue-Winged Olive
- Organism Type
- insect
- Life Stage
- dun