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.
Pattern Details
- Type
- Dry Fly
- Seasons
- summer, fall
- Hook Sizes
- #6-14
- Hook Type
- 2XL dry fly hook
- Tying Difficulty
- Intermediate
- Imitates
- Adult stoneflies (Pteronarcys, Hesperoperla, Isoperla) and large caddisflies
Recipe & Materials
- Hook
- TMC 200R or Dai-Riki 270, sizes 6-14Shop
- Thread
- 6/0 fire orange or yellow
- Tail
- Natural elk hair
- Rib (rear)
- Fine gold wire
- Body (rear)
- Orange or yellow dubbing
- Hackle (rear)
- Grizzly, palmered over rear bodyShop
- Wing
- Natural elk hair
- Body (front)
- Fluorescent orange or green dubbing
- Hackle (front)
- Grizzly, palmered over front body
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Technique & Presentation
Fish the Stimulator with a dead drift along current seams, near overhanging willows, and through pocket water. During stonefly season, cast tight to the banks where naturals fall from streamside vegetation. An upstream or up-and-across cast with a mend allows the fly to drift naturally along the bank for maximum distance.
The Stimulator is the ideal top fly in a dry-dropper setup. Tie 18-24 inches of 4X or 5X tippet off the bend of the hook and attach a bead head nymph like a Pheasant Tail or Prince Nymph. The Stimulator's buoyancy easily supports heavy droppers, and the combination allows you to fish two productive zones simultaneously.
Don't overlook the Stimulator as a late-season searching pattern. In fall, when stoneflies have long since departed, trout still respond to the substantial silhouette. Fish it through riffles and pocket water on a short line with high-sticking technique for an effective presentation that consistently produces fish.
History & Origin
The Stimulator was developed by Randall Kaufmann in the 1980s, though its exact origins are the subject of some debate. Kaufmann's creation was an evolution of earlier stonefly patterns, incorporating design elements from the Sofa Pillow and Improved Sofa Pillow while adding the palmered hackle construction that gives the fly its distinctive profile and exceptional buoyancy.
Kaufmann, owner of Kaufmann's Streamborn in Portland, Oregon, introduced the pattern in his book 'Tying Dry Flies' and it quickly became a staple of western fly fishing. The name 'Stimulator' refers to the fly's ability to stimulate strikes from trout even when no naturals are present. Today, the pattern is tied in dozens of color combinations, though orange and yellow remain the most popular for Montana fishing.
Where to Fish This Fly
Madison River
Southwest Montana
Top fly during salmonfly season
Yellowstone River
South Central Montana
Essential during stonefly season
Gallatin River
Southwest Montana
Stonefly imitation for the canyon
Colorado River
Grand County / Northern Mountains
Stonefly imitation for Byers Canyon golden stone activity
Gunnison River
Western Slope / Black Canyon Country
Golden Stonefly imitation following the Salmonfly hatch
Snake River
Northwest Wyoming / Jackson Hole
Golden stonefly imitation; also effective as attractor dry
Bighorn River (Wyoming)
North Central Wyoming
Yellow Sally stonefly imitation in early summer
New Fork River
Western Wyoming / Wind River Range
Golden stonefly and Yellow Sally imitation
Henry's Fork
Eastern Idaho
Golden Stonefly imitation for Box Canyon dry-fly fishing
South Fork Snake River
Eastern Idaho
Golden Stonefly imitation extending the big-dry window
Salmon River
Central Idaho
Stonefly dry for Golden Stones and Yellow Sallies
South Fork Boise River
Southwestern Idaho
Golden Stonefly imitation for the June-July emergence
Deschutes River
Central Oregon
Excellent golden stonefly imitation and general attractor
Metolius River
Central Oregon (Cascades)
Stonefly/attractor for riffles and pocket water. Size 8-12.
McKenzie River
Willamette Valley / Cascades
Versatile stonefly/attractor. Essential during golden stone activity. Also October caddis.
John Day River
Eastern Oregon (High Desert / Blue Mountains)
Attractor dry that doubles as a bass surface fly
Owyhee River
Southeastern Oregon
Skwala stonefly imitation, the first big dry fly event of the year. Size 8-10.
Yakima River
Central Washington
Golden Stonefly and October Caddis imitation
Methow River
North Central Washington, Okanogan County
Golden Stonefly imitation, essential early summer
Klickitat River
South Central Washington, Klickitat County
Stimulator for upper river trout and stonefly imitation
Lower Sacramento River
Northern California / Shasta County
Golden stonefly dry during May-June
McCloud River
Northern California / Shasta County
#1 dry fly for golden stonefly hatch; May-July
Upper Sacramento River
Northern California / Siskiyou and Shasta Counties
#1 dry fly for Skwala and golden stone hatches
Pit River
Northern California / Shasta County
Golden stone dry in summer
Truckee River
Eastern Sierra / Nevada and Placer Counties
Little Yellow Sally patterns in May-June
Upper Klamath River
Northern California / Siskiyou County
Stimulator for stonefly hatches and attractor fishing
Truckee River
Western Nevada / Washoe County
Attractor dry for canyon pocket water
Jarbidge River
Northern Nevada / Elko County / Jarbidge Wilderness
Stimulator attractor for fast water
Ruby Mountains / Lamoille Creek
Northern Nevada / Elko County / Ruby Mountains
Stimulator attractor for pocket water
Bruneau River
Northern Nevada / Elko County
Stimulator attractor for pocket water
Great Basin NP Streams
Eastern Nevada / White Pine County / Great Basin National Park
Stimulator attractor for pocket water
Rio Grande
Northern New Mexico / Taos County
Stimulator for spring caddis, skate or dead-drift tight to banks
Pecos River
North-Central New Mexico / San Miguel & Santa Fe Counties
Golden stonefly and stimulator attractor; follows salmonflies
Rio Chama
North-Central New Mexico / Rio Arriba County
Stimulator for golden stoneflies and October caddis
East Fork Black River
Eastern Arizona / White Mountains
Stimulator attractor dry, excellent for Apache trout
Chevelon Creek
Central Arizona / Mogollon Rim
Stimulator for attractor dry and stonefly imitation
Davidson River
Western North Carolina / Pisgah National Forest
Golden stonefly imitation for early summer hatch
Tuckasegee River
Western North Carolina / Jackson County
Golden stone imitation for faster sections
Watauga River
Northwestern North Carolina / Watauga County
Stonefly imitation for faster sections
Wilson Creek
Western North Carolina / Caldwell County
Small stonefly patterns
Linville River
Western North Carolina / Avery County
Stonefly dry for faster sections
South Toe River
Western North Carolina / Yancey County
Small stonefly patterns
West Branch Penobscot River
North-Central Maine / Piscataquis County
Stimulator in sizes 8-12 as a large attractor pattern during stonefly activity.
Androscoggin River
Northern White Mountains / Coos County
Stonefly dry for faster water. Size 10-14.
Ellis River
Mount Washington Valley / Carroll County
Stimulator for stonefly and attractor fishing in upper pocket water. Size 12-16.
Ammonoosuc River
White Mountains / Grafton County
Stimulator for stonefly and attractor fishing in upper water. Size 12-16.
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.
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.
PMD Comparadun
A flush-floating mayfly imitation that excels during Pale Morning Dun hatches. The deer hair wing creates a realistic silhouette, and the pattern sits low in the film like a natural dun. Essential during PMD hatches on the Missouri and Madison. The Comparadun design is one of the most elegant solutions in dry fly fishing. By using a fan-shaped deer hair wing instead of traditional hackle, the fly sits directly on the water surface with its body in the film. This creates a silhouette that is nearly indistinguishable from a natural mayfly dun when viewed from below, exactly the perspective that matters to a feeding trout. The PMD version, tied in pale yellow and olive, is one of the most important patterns for Montana's prolific Pale Morning Dun hatches. PMD hatches on Montana's premier rivers are events that every serious fly angler should experience. On the Missouri River below Holter Dam, PMD hatches from late June through August produce some of the best dry fly fishing in North America. The Madison River's upper sections also host excellent PMD activity. During these hatches, trout can become excruciatingly selective, and the low-riding Comparadun is often the pattern that cracks the code when parachute and traditional dun patterns fail.