What is the Trico Hatch? Fly Fishing Entomology For Fly Fishing The Trico Hatch.

by in Fly Hatches


Tricorythodes, better known as Trico’s, and also known as Tiny White-winged Blacks, White-winged Curse or Snowflake Mayfly, are the smallest mayflies found in North America. Because the trico hatch is normally both heavy and reliable, being aware of this mayfly is very important.

Their lifecycle can be as short as 5 weeks, creating multiple generations during one season.  Many rivers experience Trico hatches all summer long.

Trico Nymph: Nymphs prefer gentle currents with abundant vegetation. They are not good swimmers. Dead drifting a Trico nymph imitation can be effective at imitating the nymph.

Trico Mayfly Emerger
Trico Mayfly Emerger

Trico Emerger: Male Trico’s hatch late in the day, while females hatch early in the morning. Trico’s don’t all hatch the same way. Some nymphs swim up to the surface to hatch, some hatch underwater, then rise as a dun to the surface, and some crawl out onto the bank. Female emergers are an important part of a trout’s diet.

Male Trico. Image by Jason Neuswanger from TroutNut
Male Trico. Image by Jason Neuswanger from TroutNut
Male Trico. Image by Jason Neuswanger from TroutNut
Male Trico. Image by Jason Neuswanger from TroutNut
Female Trico. Image by Jason Neuswanger from TroutNut
Female Trico. Image by Jason Neuswanger from TroutNut
Mallard's Tanked Trico Spinner
Mallard's Tanked Trico Spinner
Angel Wing Trico Spinner
Angel Wing Trico Spinner
Eric's Trico Spinner
Eric's Trico Spinner

Trico Dun and Spinner: Once airborne, Trico’s swarm over the river and mate. Males immediately fall to the water with spent wings, and the trout begin feeding. A few hours later, females return to the water to deposit their eggs, die, and trout continue to feed. The abdomen of a male spinner is generally black, while the female is olive. Begin fishing with a black spinner, but watch the naturals, and switch over to olive at some point.

Trout often become very selective when feeding on emergers and spinners. Single out a feeding trout, and drift the fly down that exact feeding lane. Try to time your fly to the rhythm of the trout for better success.

There is nothing more exciting than successfully sight fishing for a feeding trout in this manner.

Trico Adult Mayflies
Trico Nymphs & Emergers

Trico Mayfly Collection

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