When does the Japanese Glossosoma hatch?

April–October, typically 12:00–17:00. It starts from about 10°C, peaks around 16°C and tails off by 22°C.

What flies imitate the Japanese Glossosoma?

Elk Hair Caddis, CDC Sedge, Sakasa Kebari, typically on a #18–16 hook.

How big is the Japanese Glossosoma?

Adult stage: 5–8mm. That matches a #18–16 hook.

Caddis · Aquatic insect

Glossosoma (Japan)

Glossosoma nigrior

Size

5–8mm

Hook size

#18–16

Hatch window

Season April–OctoberPeak time 12:00–17:00

Water temperature

16° peak

10°22°

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

Elk Hair Caddis

CDC Sedge

Sakasa Kebari

Ecology

Rivers only

Where you'll find this

East AsiaPresent

Present throughout

Identification

Glossosoma nigrior is a species of little black caddisfly in the family Glossosomatidae. It is found in North America.

Caddis →