Learn/Fly Box/Nymph/Tungsten Bug
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Nymph

Tungsten Bug

Fast-sinking small dark nymph
Trout · GraylingSubsurface

Tungsten-beaded small dark nymph that sinks fast to the feeding zone — covers Iron Blue and autumn-olive nymphs.

Fish this when

In early spring or autumn on faster pocket water when Iron Blue or dark olive nymphs are active, where the extra tungsten weight is needed to get a size 16-20 fly down before the drift is over.

Why it works

Its dense tungsten bead gets a genuinely tiny nymph to the bottom of a fast seam fast enough to be in the zone for the whole drift, which a lighter dressing in that size simply can't manage.

Naturals it imitates
small weighted olive/Iron Blue nymph
Typical zone & fishable range
usually
Surface
Film
Subsurface
Deep
Setup sensitivity: medium
Hook range#16–20
Quick facts
Tying difficulty
Beginner-friendly