Trico Spinner
A tiny (#18-22) spent-wing pattern that imitates the Tricorythodes spinner fall. Trico mornings on the Missouri River are legendary, with pods of rising trout slurping tiny spinners from the surface. Requires fine tippet and precise presentation. The Trico spinner fall is one of fly fishing's most challenging and rewarding experiences. Each morning from mid-July through September, clouds of tiny Tricorythodes mayflies mate, the females deposit their eggs, and both sexes fall spent on the water with wings outstretched. Trout line up in feeding lanes and sip these minute insects with metronomic regularity. The Trico Spinner, with its splayed hackle-fiber or poly-yarn wings and tiny thread body, is the pattern purpose-built for this event. The challenge of Trico fishing is twofold: the flies are tiny, and the trout are selective. On the Missouri River, trout feeding during Trico spinner falls routinely refuse flies that are a single hook size off, that drag even slightly, or that have a wing profile that does not match the naturals. This is technical dry fly fishing at its finest, demanding long leaders, fine tippets, precise casting, and patience. The reward is steady surface action with large, well-conditioned trout.
Pattern Details
- Type
- Dry Fly
- Seasons
- summer, fall
- Hook Sizes
- #18-24
- Hook Type
- Fine-wire dry fly hook
- Tying Difficulty
- Advanced
- Imitates
- Tricorythodes spinner (spent adult mayfly)
Recipe & Materials
- Hook
- TMC 101 or Tiemco 501, sizes 18-24Shop
- Thread
- 10/0 or 12/0 black
- Tail
- Light dun Micro Fibetts, split
- Abdomen
- Olive-brown or black thread, thin
- Thorax
- Black superfine dubbing
- Wing
- White poly yarn or hackle tips, spent
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Technique & Presentation
Trico fishing requires an upstream or up-and-across presentation to individual rising trout. Identify a feeding fish, determine its rhythm, and place your fly 2-3 feet upstream so it drifts naturally into the trout's feeding lane. The cast must be accurate to within inches; a fly that drifts even a foot off the feeding lane will be ignored.
Use a 12-15 foot leader tapered to 6X or 7X. Fluorocarbon tippet can help with reduced visibility, but its stiffness may cause micro-drag issues. Many experienced Trico anglers prefer nylon for its suppleness. Make sure your leader turns over properly despite the light tippet; a pile cast or reach cast can help achieve a drag-free drift on complex currents.
Timing matters. Trico spinner falls typically occur from about 8 AM to 11 AM, depending on temperature and cloud cover. Arrive early to observe the swarm and be ready when spinners start hitting the water. The fishing window may last an hour or three hours. Bring multiple sizes (#20 and #22 are most common) and be prepared to experiment until you find what the fish want.
History & Origin
Trico spinner patterns have evolved significantly since the Tricorythodes hatch was first recognized as a major fishing opportunity in the 1960s and 1970s. Vince Marinaro, Charles Fox, and other Pennsylvania limestone creek pioneers were among the first to develop effective Trico patterns for the spring creeks of central Pennsylvania.
The patterns migrated westward as anglers discovered prolific Trico hatches on western rivers, particularly the Missouri River below Holter Dam and the Bighorn River in Montana. Today's Trico Spinner patterns are refined to their essence: minimal thread bodies, precisely split tails, and spent wings of the thinnest possible material. The pattern represents the ultimate exercise in minimalist fly tying, where every fiber matters.
Where to Fish This Fly
Missouri River
Central Montana
Trico mornings are legendary
South Platte River
Front Range / South Park
Trico spinner for technical morning fishing in Cheesman
North Platte River
Central Wyoming
Technical Trico mornings produce exceptional fishing
Green River
Southwest Wyoming
Trico spinner falls on Seedskadee summer mornings
Bighorn River (Wyoming)
North Central Wyoming
The signature Bighorn pattern; Trico spinner falls define this fishery
New Fork River
Western Wyoming / Wind River Range
Trico spinner in the slower meadow sections
Henry's Fork
Eastern Idaho
Trico Spinner for technical morning fishing on the Ranch
Silver Creek
Central Idaho / Sun Valley
The Silver Creek signature pattern: Trico spinner for dawn feeding
Crooked River
Central Oregon
Trico spinner for challenging early morning spinner falls
Rocky Ford Creek
Central Washington, Grant County
Trico Spinner for technical morning spinner falls. Size 20-22
Hat Creek
Northern California / Shasta County
Trico spinner for technical morning fishing
Fall River
Northern California / Shasta County
Trico spinner for late summer technical fishing
East Walker River
Eastern Sierra / Mono County
Trico spinner for August morning fishing
Hot Creek
Eastern Sierra / Mono County
Trico spinner for technical late summer fishing
East Walker River
Western Nevada / Lyon County
Morning Trico spinner falls August-September
Magalloway River
Western Maine / Oxford County
Trico Spinner in sizes 20-22 for morning spinner falls on calm pools.
Androscoggin River
Northern White Mountains / Coos County
Trico spinner for morning falls. Size 20-24.
Saco River
Mount Washington Valley / Carroll County
Trico spinner for morning falls. Technical fishing. Size 20-24.
Battenkill River
Southern Vermont / Bennington County
For morning Trico spinner falls. Technical presentation required. Size 20-24.
White River
Central Vermont / White River Valley
For morning Trico spinner falls on calm summer mornings. Size 20-22.
Penns Creek
Central Pennsylvania / Centre County
Trico spinner pattern for July-September morning fishing
Spring Creek
Central Pennsylvania / Centre County
Essential for Trico spinner falls July-September
Spruce Creek
Central Pennsylvania / Huntingdon County
Trico spinner for morning falls
Yellow Breeches Creek
South Central Pennsylvania / Cumberland County
Trico spinner for morning falls
Big Spring Creek
South Central Pennsylvania / Cumberland County
Trico spinner for morning falls
Related Dry Fly Patterns
Parachute Adams
The most versatile dry fly ever created. The Parachute Adams imitates a wide range of mayflies and serves as an effective searching pattern when no specific hatch is occurring. The white parachute post makes it easy to track on the water. Originally tied with conventional upright wings, the parachute version wraps the hackle horizontally around the post, allowing the fly to land flush on the surface with a more realistic silhouette. This low-riding profile is why many experienced anglers prefer it over the standard Adams. The mixed brown and grizzly hackle suggests the mottled coloring of countless mayfly species, from tiny Baetis to larger Callibaetis. On Montana waters, the Parachute Adams is the quintessential searching pattern. When you arrive at the river and nothing is hatching, tie on a Parachute Adams in size #14 or #16 and start prospecting. During active hatches, sizing down to match the naturals makes this fly deadly. It works on every Montana river from the riffles of the Madison to the spring creek-like waters of the Missouri below Holter Dam.
Elk Hair Caddis
Al Troth's iconic caddis imitation is a must-have on every Montana river. The elk hair wing provides excellent flotation, and the pattern effectively matches adult caddisflies throughout the season. Dead-drift, skate, or twitch it; all methods produce fish. The Elk Hair Caddis is one of those rare patterns that works from the moment caddisflies start appearing in spring through the last hatches of fall. The tent-shaped elk hair wing perfectly mimics the profile of a resting adult caddis, while the palmered hackle gives the fly exceptional buoyancy and creates the impression of legs touching the surface. Its durability is legendary; a well-tied Elk Hair Caddis can take dozens of fish before needing replacement. In Montana, caddis hatches are prolific on every major river. Mother's Day caddis hatches on the Yellowstone in late April and May are among the most anticipated events of the season. The Elk Hair Caddis is equally effective on the rock gardens of the Gallatin, the braided channels of the upper Madison, and the tailwater sections of the Missouri. Vary the body color between tan, olive, and green to match local populations.
Stimulator
An outstanding attractor dry fly and stonefly imitation. The Stimulator excels as a top fly in a dry-dropper rig. Larger sizes (#6-8) match salmonflies and golden stones, while smaller sizes (#12-14) suggest various stoneflies and caddis. The Stimulator's genius lies in its buoyancy and suggestive profile. The combination of a heavily palmered hackle, elk hair wing, and robust body allows it to ride high on turbulent water where lesser flies would drown. The swept-back wing silhouette works as both a stonefly and large caddis imitation, making it effective even when no specific insect is hatching. Trout see the Stimulator and recognize it as a substantial, calorie-rich meal worth rising for. In Montana, the Stimulator truly shines during stonefly season on the Madison, Yellowstone, and Gallatin rivers. Tie on a size #6 orange Stimulator during the salmonfly hatch in late June and fish it tight to the banks. As summer progresses, switch to smaller sizes in yellow for golden stones. The Stimulator also serves as an excellent indicator fly for a heavy nymph dropper, especially when wading pocket water and riffles where it can be challenging to track a strike indicator.
Chubby Chernobyl
A modern foam attractor pattern that has become a Montana staple. Virtually unsinkable, the Chubby floats heavy nymph droppers and draws aggressive strikes from trout looking for a large, easy meal. Available in numerous colors. The Chubby Chernobyl represents the evolution of the foam hopper and stonefly genre. Its layered foam body creates a nearly indestructible fly that requires no floatant and rides high on even the roughest water. The rubber legs provide enticing movement, and the flash wing catches light in a way that grabs attention from trout holding deep. Whether tied in tan, purple, pink, or any other color, the Chubby simply produces fish. Montana guides have embraced the Chubby Chernobyl as their go-to dry-dropper indicator fly, and for good reason. It supports one or even two heavy nymphs without sinking, it is visible at long distances, and trout eat it with startling aggression. On the Madison, Yellowstone, and Gallatin rivers, more fish are likely caught with a Chubby on top than any other dry fly. Its effectiveness extends from early July through October, covering the heart of Montana's fishing season.
Purple Haze
A Montana-born variation of the Parachute Adams with purple dubbing. Created in the Gallatin Valley, this pattern has become a regional favorite that outperforms the standard Adams on many days, particularly during BWO and PMD hatches. The Purple Haze takes the proven Parachute Adams template and adds a subtle twist: a body of purple dubbing that seems to trigger something in trout that the standard gray does not. While purists may argue the color is unnatural, the results speak for themselves. Montana anglers have reported for years that the Purple Haze consistently outfishes the standard Adams, particularly on rivers that receive heavy fishing pressure. Theories about why the purple works vary. Some believe that the color more accurately represents the UV spectrum reflected by natural mayflies. Others suggest that the slightly different hue simply stands out enough on pressured water to be noticed without being refused. Whatever the reason, the Purple Haze has earned its place in the top tier of Montana dry flies. It is especially effective on the Gallatin, Madison, and Yellowstone rivers from late spring through early fall.
X-Caddis
Craig Mathews' brilliant caddis emerger pattern sits in the surface film, imitating a caddis struggling to break through the meniscus. Deadly during caddis hatches when fish refuse higher-riding patterns. The trailing shuck is key to its effectiveness. The X-Caddis fills a critical gap in the caddis life cycle that most fly boxes lack. While traditional dry flies like the Elk Hair Caddis ride high on the surface, the X-Caddis sits flush in the film with its body partially submerged and a trailing Z-lon shuck extending behind. This precisely imitates the moment when a caddis pupa breaks through the surface and begins to shed its pupal shuck, the most vulnerable stage for the insect and the moment when trout feed with the least caution. On Montana's caddis-rich rivers, the X-Caddis can make the difference between a frustrating day of refusals and a banner day of steady action. When you see trout rising during a caddis hatch but refusing your Elk Hair Caddis, the X-Caddis is the answer. It is particularly effective on the Yellowstone during the Mother's Day caddis hatch, on the Madison during summer evening hatches, and anywhere trout have become educated to conventional caddis patterns.