Dark Blue Sedge

Overview

The Dark Blue Sedge is a caddisfly (order Trichoptera) known for its dark blue to slate body and famously elusive hatch. Found in cold, clear, fast-moving rivers from late spring into early summer, its brief and subtle emergence often leaves trout rising selectively and anglers frustrated — fly fishing writer Gary LaFontaine nicknamed it the "Slap-in-the-Face Caddis" for exactly that reason. Hook sizes: 14 to 18.

Nymph

Nymphs are slender, dark brown to olive, running 0.5 to 1 inch. They're clingers, working rocks and submerged vegetation in fast water and migrating to shallower water as they near emergence. Dead-drifted presentations near the bottom or structure are effective. Hook sizes: 14 to 18.

Dry/Adult

Adults run 0.5 to 1 inch, with a dark blue to slate body and translucent, faintly gray-tinted wings. The hatch moves fast and quietly, making timing difficult, and trout often key in briefly before dropping off — the exact trait behind LaFontaine's nickname. Adults are usually seen fluttering on the surface or perched on streamside vegetation. Hook sizes: 14 to 18.

Curated by the IdentaFly fly fishing team.