RS2 Emerger – All-Purpose Mayfly Emerger for Trout

The RS2 (Rim Semi-Spent) is a deceptively simple emerger that has been fooling selective trout on western tailwaters and spring creeks since Rim Chung created it in the 1970s. The sparse body, small wing tuft, and minimal profile make it nearly invisible on the water — which is exactly why trout eat it. When fish are sipping emergers and refusing everything else in your box, the RS2 is the pattern that finally gets the take.

This fly doesn't look like much in your hand. But underwater, in the surface film, it perfectly replicates a small mayfly or midge stuck in its shuck and trying to hatch. That vulnerability trigger is what makes trout eat it with confidence.

When to Fish It

Year-round during any small mayfly or midge emergence. It's deadly during BWO hatches, PMD hatches, Trico spinner falls, and heavy midge activity. Fish it on a dead-drift in the surface film with a long leader (12+ feet) and fine tippet (5X-7X). Also effective as a dropper below a more visible dry fly. The RS2 is a technical fly for technical situations — use it when precision matters.

Specs

• Type: Emerger — Mayfly / midge imitation
• Hook: Fine wire, small profile
• Weight: Unweighted — sits in the surface film
• Best for: Trout — tailwaters, spring creeks, technical flat water
• Technique: Dead-drift in surface film, dry-dropper trailer, fine tippet

Why Anglers Stock This Fly

The RS2 has been a secret weapon on western tailwaters for decades. Guides on rivers like the South Platte, Frying Pan, and Green River keep a row of RS2s in their box because they solve the most frustrating problem in fly fishing — visible, rising fish that won't eat. It's one of the most important patterns for anyone who fishes technical water. Hand-tied with quality materials by tiers with over 30 years of experience.

🎣 Build your emerger arsenal? Browse our Emerger collection for more surface-film patterns.