When does the Golden Stone hatch?

June–August, typically 10:00–dusk. It starts from about 11°C, peaks around 14°C and tails off by 18°C.

What flies imitate the Golden Stone?

Golden Stone, Stimulator, Chubby Chernobyl, typically on a #6–4 hook.

How big is the Golden Stone?

Adult stage: 20–28mm. That matches a #6–4 hook.

Stonefly · Aquatic insect

Golden Stone

Hesperoperla pacifica

Size

20–28mm

Hook size

#6–4

Hatch window

Season June–AugustPeak time 10:00–dusk

Water temperature

14° peak

11°18°

How fish feed on it

Adult insects on the water are inefficient — a caddis skittering to lay eggs, a stonefly blundering about after crawling out, neither built for elegance. Trout treat it as an easy meal and a bit of theatre at once, chasing a moving fly with more enthusiasm than they'd ever give a still one. Movement is the tell; a static adult imitation often just sits there unloved.

Flies that imitate this

Golden Stone

Stimulator

Chubby Chernobyl

Ecology

Rivers onlySpate rivers

Where you'll find this

North America — WestPresent

Present throughout

Identification

Hesperoperla pacifica , the golden stonefly , is a species of common stonefly in the family Perlidae. It is found in North America. Its nymph is distinguished from other perlids by a pale, hourglass-shaped mark on its head.