Dark Cahill Wet

Dark Cahill Wet

The Dark Cahill Wet is a time-tested classic that has been fooling trout for well over a century — a traditional wet fly pattern that imitates a broad range of drowned or emerging mayflies with its dark, mottled profile and soft, flowing hackle. Originally tied as a dry fly by Dan Cahill in the late 1800s, the wet version fishes subsurface with a lifelike, breathing action that trout find irresistible, particularly in the evening when mayflies are hatching and spent insects are washing through the current. Simple, elegant, and proven across generations of anglers, the Dark Cahill Wet is a foundational pattern that belongs in every wet fly box.

Pattern Details

• Style: Classic wet fly / mayfly emerger and drowned dun imitation
• Body: Dark, mottled profile — imitates a wide range of darker mayfly species including Cahills, March Browns, and drowned duns
• Hackle: Soft collar — pulsing, lifelike movement that breathes naturally in the current
• Wing: Traditional wet fly wing — swept back for a streamlined, subsurface silhouette
• Best water: Runs, riffles, pools, and tailouts — most effective during evening mayfly hatches and in the hour after a hatch ends
• Target species: Trout
• Techniques: Swung across and downstream on a tight line during evening hatches; dead-drifted through runs and seams; lifted at the end of the drift to imitate an ascending emerger; fished in a team of wet flies on a multi-fly rig
• Sizes available: 12, 14

A century-proven wet fly that still earns its keep — the Dark Cahill Wet's classic profile and soft hackle action make it one of the most reliable evening patterns for trout on moving water.