When does the Trico hatch?

July–September, typically 07:00–11:00 (morning spinner fall). It starts from about 12°C, peaks around 17°C and tails off by 24°C.

What flies imitate the Trico?

Trico Spinner, Trico Dun, CDC Trico, Trico Comparadun, typically on a #20–18 hook.

How big is the Trico?

Spinner stage: 3–5mm. That matches a #20–18 hook.

Mayfly · Aquatic insect

Trico

Tricorythodes explicatus

Size

3–5mm

Hook size

#20–18

Hatch window

Season July–SeptemberPeak time 07:00–11:00 (morning spinner fall)

Water temperature

17° peak

12°24°

How fish feed on it

A morning spinner fall, which is what makes trico fishing distinctive and what catches people out expecting an evening. The swarm forms over the river soon after first light, drops spent within a couple of hours, and the fish feed in flat glassy water on something the size of a comma. Long fine tippet, tiny fly, and be finished by lunch.

Flies that imitate this

Trico Spinner

Trico Dun

CDC Trico

Trico Comparadun

Ecology

Rivers & stillwaterTailwatersChalk streams

Where you'll find this

North America — WestPresent

Present throughout

Mayflies →