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Matching the Hatch

Dry fly strategies for matching the hatch, with nymphs and emergers always in the mix for when fish aren't looking up.

By IdentaFly editorial team

Fly fishing editors & anglers

Published Apr 15, 2026 · Updated Apr 16, 2026

Matching the Hatch: Dry Flies, Nymphs & Emergers

“Matching the hatch” means choosing a fly that imitates whatever insects the fish are actively feeding on. It's both an art and a science — and getting it right is one of the most satisfying experiences in fly fishing.

What is a hatch?

Aquatic insects — mayflies, caddisflies, stoneflies, and midges — spend most of their lives as nymphs or larvae underwater. When conditions align (water temperature, light, season), they emerge in large numbers as adults. That emergence is the “hatch.” Fish key in on it immediately, often abandoning their usual lies to feed aggressively on the surface.

Dry flies: when fish are rising

If you can see fish rising to the surface, there's a hatch on. Watch the water for a few minutes before reaching for a fly — try to spot the insects on the water or in the air. Are they mayflies with upright wings? Caddis fluttering in erratic patterns? Midges forming clusters?

Match the size and silhouette first, then color. A size 16 PMD doesn't need to be the exact shade of yellow-olive the naturals are — it needs to float correctly in the right feeding lane and not drag. Presentation beats imitation most of the time.

Nymphs and emergers: when fish aren't looking up

Most trout feeding happens subsurface, even during a visible hatch. Nymphs and emergers — flies that imitate insects in the water column — are often more productive than dries because fish intercept the insects before they ever reach the surface.

An emerger pattern (a fly designed to ride right at the surface film) can be the most effective option during a hatch — fish see drowned or partially-emerged insects as easy targets. Soft hackles, Klinkhammers, and RS2s all work this zone effectively.

Using IdentaFly's hatch forecast

IdentaFly's hatch forecast tool shows you which insects are most likely to be active near any location, based on water temperature and seasonal timing. Use it before your trip to build a short list of flies to carry — then refine on the water based on what you actually see.