Learn/Fly Box/Nymph/Isonychia Nymph
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Nymph

Isonychia Nymph

Bank-crawling fast swimmer
Trout · GraylingSubsurface

Streamlined fast-swimming nymph of the Slate Drake (Isonychia) — crawls to the bank to emerge, so the nymph is the key stage.

Fish this when

In late summer on faster eastern freestone rivers, dead-drifted or swung tight to the bank and structure as naturals migrate toward the margins.

Why it works

Isonychia nymphs crawl out to the bank rather than hatching mid-river, so fishing tight to the edge puts the fly exactly where the naturals are concentrating, whether or not anything is rising.

Naturals it imitates
Slate Drake / Isonychia swimmer nymph
Typical zone & fishable range
usually
Surface
Film
Subsurface
Deep
Setup sensitivity: medium
Hook range#10–12
Quick facts
Tying difficulty
Intermediate