Trico
Also called Tricorythodes, Trico hatch, Trico spinner fall
Trico is a tiny mayfly (genus Tricorythodes) best known for dense summer morning hatches and spinner falls. On many trout rivers it brings selective fish and fine-tippet dry-fly fishing.
- Group
- Mayfly hatches
- Category
- Entomology & forage
- Level
- Intermediate
- Water
- Freshwater
Last updated
What Trico means
On the water, “trico” usually means the hatch, not the bug’s full name. The insects are small, and the most visible event is often the spinner fall, when spent adults collect in slicks and foam lines and trout feed steadily.
Trico fishing is commonly a two-part deal. First comes the mating swarm and spinner fall, which calls for low-riding spinner patterns. Earlier in the morning, and sometimes between rises, nymphs can be important, especially in slower water where fish feed subsurface before the surface event really gets going.
Because the flies are so small, details that don’t matter on bigger hatches start to matter here: a clean drift, the right silhouette, and a leader that will turn over a light fly without dragging it. Many anglers fish them with long leaders and fine tippet, and they plan around the morning timing rather than the afternoon.
Why it matters on the water
If someone says “the tricos are on,” it’s a heads-up about pace and precision. It usually means slower water, steady rises, and trout that will ignore a fly that lands hard or drags even a little. That changes how you approach a run: longer casts, better angles, and more patience between presentations.
It also helps with fly choice. A lot of mayfly hatches are nymphs and emergers first, then adults. Tricos often feel inverted on many rivers: the spinner fall is the main show. Knowing that keeps anglers from cycling through random dries when a simple spinner pattern in the right size and color is what the fish are keyed on.
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Read next
- Blue-winged olive“Blue-winged olive” (BWO) is the common fly-fishing name for several small mayflies in the Baetis group. Anglers use it to describe the hatch and the flies used to match it.
- Clinch knotA clinch knot is a simple knot for tying tippet or leader to a fly’s eye. It’s quick to tie and common for dry flies, nymphs, and small streamers.
- SpinnerA spinner is a dry fly that imitates an adult mayfly after it has mated and fallen spent on the water, usually with wings laid flat to the sides.
- Zebra MidgeA Zebra Midge is a small, slim midge-larva or pupa imitation, usually tied with a ribbed body and a bead. It’s a common choice for trout feeding on tiny insects.