Hexagenia
Imitates: Adult Hexagenia limbata mayfly (largest North American mayfly)
Quick Reference
- Best Sizes
- #6-10 (3XL or 4XL hooks)
- Best Season
- Late June through July (evening into dark)
- Best Conditions
- Silt-bottom rivers and lakes, dusk to midnight, calm water, Hex hatch
- Water Temp
- 65-72°F
- Recommended Tippet
- 3X-4X mono (fish are eating, not inspecting)
How to Rig It
Single dry on a 9 ft 3X leader. Use a heavy leader — Hex eats are violent and often from the largest fish in the system.
How to Present It
Cast across-and-down to rises and dead-drift. In the dark, listen for the rise — set on sound, not sight.
Why It Works
Hexagenia limbata is the largest mayfly in North America (over an inch long), and the hatch triggers the biggest brown trout in the river to feed on top — often the only night they do. Cream-yellow body matches the natural; pale wing is visible against the dusk sky.
History
The Hex hatch on Michigan's Au Sable, Wisconsin's Bois Brule, and Pennsylvania's Penns Creek is a legendary night-fishing tradition. Anglers wait all year for the late-June emergence — it's when 24-inch browns feed in shallow water.
Pro Tip
Don't fish the Hex hatch in daylight. The big browns wait for full dark. Be on the water by 9 PM with a headlamp on red mode, and listen as much as look. The takes sound like a toilet flushing.
Frequently Asked Questions
When is the Hex hatch?+
Late June through mid-July depending on latitude and water temperature. Peak is usually within a 2-week window when water hits 65-68°F at dusk.
Where can I fish the Hex hatch?+
Best Hex water: Michigan's Au Sable (Holy Waters), Wisconsin's Bois Brule, Pennsylvania's Penns Creek and Pine Creek, and silt-bottom lakes across the upper Midwest.
What size Hex fly should I use?+
#6 or #8 on a 3XL or 4XL hook. The naturals are over an inch long — go big or get refused.
Not sure if Hexagenia is right today?
Get a fly recommendation based on live water temp, flow, sky, and time of day for any river in the US.
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