Best Midge Patterns for Trout: 12 Flies Every Angler Needs

Introduction

Ask any guide what trout eat more than anything else, and you’ll hear the same answer: midges. These tiny insects make up the backbone of a trout’s diet throughout the year, but especially during winter when larger bugs are nowhere to be found. Knowing the best midge patterns for trout separates anglers who catch fish year-round from those who hang up their rods when temperatures drop.

The challenge with midges isn’t finding them—they’re virtually everywhere. The challenge is matching the right life stage, the right size, and the right presentation. Trout sipping in a foam line need a different fly than trout holding deep in a cold winter run. This guide walks through 12 patterns that cover every situation you’ll encounter on Western tailwaters and freestone streams.

Understanding Which Stage to Match

Before diving into specific patterns, you need to understand what trout are actually eating. Midges progress through four life stages, and each calls for a different fly and presentation.

Larvae live in the substrate and get dislodged by current or feeding activity. They’re simple, worm-like creatures—often red, olive, or cream. Trout eat them near the bottom, so you fish larva patterns deep with weight.

Pupae are the transitional stage, and they’re arguably the most important for anglers. When larvae transform into pupae, they develop the distinctive segmented body with a bulbous thorax that makes patterns like the RS2 so deadly. Pupae drift slowly toward the surface to emerge, making them vulnerable throughout the water column.

Emergers get stuck in the surface film—sometimes for extended periods. This is when trout feed most actively, sipping bugs trapped in that meniscus layer. Emerger patterns suspend in the film, imitating that vulnerable moment.

Adults ride the surface briefly before flying off to mate. Trout key on clusters of adults, which is why patterns like the Griffith’s Gnat work so well—they suggest multiple bugs grouped together.

Larva Patterns

Reliable larva imitations produce year-round, and they’re where every midge box should start.

1. Zebra Midge

The Zebra Midge is the most essential midge larva pattern in existence. Period. Its simplicity—just thread and wire ribbing over a bead head—perfectly captures the segmented look of a midge larva without overcomplicating things.

Carry Zebra Midges in black, red, and olive. Size 20 is the workhorse, but drop to 22 when fish get selective. The bead head gets the fly down fast, which matters when you’re fishing four to six feet of depth on a cold winter morning.

Fish Zebra Midges on a dead drift near the bottom. They work great as the point fly in a two-fly nymph rig, with a larger attractor pattern above them. On the Green River Section A below Flaming Gorge, a black or red Zebra Midge accounts for more winter trout than any other fly in the box.

2. Blood Midge (Thread Midge)

The Blood Midge strips the Zebra Midge down even further—just red thread wrapped over a hook, sometimes with a copper bead. The red color imitates chironomid larvae that contain hemoglobin, earning them the “blood” nickname.

This pattern shines in stillwater and slow tailwater pools where midge larvae accumulate. Size 22–24 in bright red thread fishes well below an indicator or as the dropper behind a larger nymph.

3. Disco Midge

When water clarity drops or light fades, the Disco Midge adds flash to the basic midge larva template. Holographic tinsel creates a subtle sparkle that helps trout locate the fly in low-visibility conditions.

I tie these in red and black. The flash can make a difference during overcast winter days when visibility in the water column drops. Fish them the same way you’d fish a Zebra Midge—deep and slow.

Pupa Patterns

Pupa imitations cover the most productive stage to target, so this is where your midge box earns its keep.

4. RS2 (Rim’s Semblance 2)

If you could only fish one midge pupa pattern for the rest of your life, make it the RS2. Rim Chung designed this pattern, and its sparse profile perfectly suggests an emerging midge pupa. The CDC fiber wing mimics the air bubble trapped under the pupal shuck during emergence.

The RS2 works anywhere in the water column. Fish it deep during non-hatch periods, then move it higher as you see fish rising. In sizes 20–24, this fly fools educated tailwater trout that have seen every commercial pattern on the market.

On the San Juan River below Navajo Dam, the RS2 in gray or black produces through the entire winter. Swing it slightly at the end of a drift to trigger strikes from fish that followed but didn’t commit.

5. Mercury Midge

The Mercury Midge uses a glass bead to suggest the air bubble that forms inside a pupa’s shuck during emergence. That tiny bit of flash mimics the real thing better than synthetic materials.

Black is the go-to color, but olive works well during spring emergences. Fish this pattern in the top 12–18 inches of the water column during active midge hatches. The glass bead also adds just enough weight to break the surface tension, helping the fly hang vertically like a natural pupa.

6. Top Secret Midge

Pat Dorsey’s Top Secret Midge has become a Colorado tailwater staple. The sparse design features a slim thread body, minimal wing case, and tiny flash-back element that suggests the developing adult inside the pupal shuck.

This pattern excels when trout are feeding subsurface but not on the bottom—that middle zone where pupae drift upward. Sizes 20–22 in gray or olive cover most situations. On the Bighorn River below Yellowtail Afterbay, the Top Secret consistently outperforms bulkier patterns when fish push up into riffle tailouts.

Emerger Patterns

7. Juju Bee Midge

Charlie Craven’s Juju Bee uses closed-cell foam to keep the fly suspended in the surface film—exactly where emerging midges get trapped. The realistic segmentation and slim profile make this a must-have for surface-film feeders.

Fish the Juju Bee during visible midge hatches when you see trout making subtle rises. The take is often just a dimple or a flash. Size 22 in black or gray handles most situations on Western tailwaters.

8. Mole Fly

The Mole Fly’s fuzzy mole-skin thorax creates a distinct silhouette in the film. It’s a more visible pattern than pure thread-body emergers, making it useful when you’re struggling to track smaller flies in fast or broken water.

This pattern works best during afternoon emergences when fish commit to the surface. On the Missouri River below Holter Dam, the Mole Fly’s bulkier silhouette helps you stay on the fly when wind chops the surface and smaller emergers disappear.

9. CDC Midge Emerger

CDC (cul de canard) feathers float naturally and move with the slightest current, making CDC Midge Emergers incredibly lifelike. The sparse CDC wing suggests the crumpled adult wings of a midge struggling to escape its shuck.

Tie these in sizes 20–24 with minimal CDC—two or three fibers are plenty. Too much CDC and the fly sits too high, losing that half-in, half-out emerger profile. Gray and black cover 90% of Western midge hatches.

Adult and Cluster Patterns

10. Griffith’s Gnat

The Griffith’s Gnat imitates a cluster of mating midges on the surface. Palmered grizzly hackle over peacock herl creates a buggy silhouette that trout find irresistible when midges are swarming.

This is often the first dry fly I reach for during winter midge activity. Size 18–20 works for most situations, though you can drop to 22 when fish get picky. The peacock herl adds enough body that trout will move for this fly even in cold water.

Fish Griffith’s Gnats on a dead drift over rising fish. Don’t overlook the slow water—back eddies, foam lines, and pool tailouts concentrate midge clusters and the trout that feed on them.

11. Parachute Midge

Sometimes visibility matters more than perfect imitation. The Parachute Midge adds a small post—usually white or orange—that lets you track the fly in broken water or at distance.

The pattern beneath the post is classic midge adult: slim body, sparse hackle, minimal wing. Sizes 18–22 work best. This fly has saved plenty of days on the Lower Provo River when afternoon canyon winds make tracking standard midge patterns nearly impossible.

12. Palomino Midge

The Palomino Midge combines CDC with a dubbed body for a fuller adult pattern. The yellow or cream-colored CDC makes it visible against dark water backgrounds—a common scenario on tannin-stained creeks or overcast days.

Treat this as your “search” dry fly when you know midges are present but haven’t located feeding fish yet. The added visibility helps you cover water efficiently without losing track of the fly.

Reading Conditions Before You Drive Out

Even a perfect midge box can’t save a day when the river isn’t fishable. Winter flows on Western tailwaters swing more than people expect—reservoir managers bump releases for ice control, downstream demand, or maintenance, and what was a 220 cfs trickle on Tuesday can be 600 cfs of off-color push by Friday morning.

The fishable window for midge work is usually narrower than the catch-all “tailwater range.” Most Colorado and Wyoming tailwaters fish best for midges between roughly 150 and 450 cfs—low enough that fish stack in predictable seams, high enough that there’s actual current to deliver bugs. Above that, the foam lines blow out and trout abandon the soft spots that make midge fishing work. Below it, fish get spooky and selective in slick water.

Before committing to a two-hour drive, pull up River Conditions in the FlyGuysNLies app—if flows pushed above 800 cfs overnight, that run you had in mind just became a wade-in-the-parking-lot situation, and you’re better off rerouting to a more sheltered tailwater. Pair that with the Trout Unlimited coldwater conservation resources for context on why these tailwater fisheries are worth protecting, and check the current Colorado Parks and Wildlife fishing regulations before you rig up if you’re traveling between drainages or counties.

Building Your Midge Box

You don’t need dozens of midge patterns to fish well. A focused selection covering each life stage in key colors and sizes handles 95% of situations.

Essential Midge Box:

Presentation Tips That Make the Difference

Having the right patterns matters, but presentation separates good days from great ones.

For larvae, fish them deep. Add weight if needed to stay near the substrate, and remember that any unnatural movement kills the presentation—dead drift is the whole game.

For pupae, vary your depth. Start near the bottom and gradually move your indicator or dry-dropper setup higher until you find where fish are holding. The slow swing at the end of a drift often triggers strikes from trout that followed without committing.

For emergers and adults, long, fine leaders are non-negotiable. Go to 6X or 7X fluorocarbon tippet in clear tailwater situations. Mend aggressively to eliminate micro-drag that spooks educated trout.

And whatever you do, watch the naturals. If you see midges clustered on the surface, fish a Griffith’s Gnat. If you see subtle rises with no visible adults, switch to an emerger or pupa. Let the fish tell you what they want.

When to Fish Each Pattern

Early morning (before 10 AM) is larva and deep-pupa time. Fish near the bottom in runs and tailouts where bugs collect overnight.

Mid-morning into early afternoon is the transition. Start deep, but watch for rising fish as temperatures climb and emergence begins.

Peak emergence on a winter day usually runs from 11 AM to 2 PM. This is prime time for RS2s and Juju Bees suspended high in the column.

Late afternoon brings the adult window. Spent midges collect in foam lines and eddies, and Griffith’s Gnats shine here right up until the light fades.

Final Thoughts

The best midge patterns for trout aren’t complicated—they’re refined. Simple flies that accurately suggest each life stage, presented with attention to depth and drift, will catch trout when nothing else works.

Start with the Zebra Midge and RS2 if you’re building a midge box from scratch. Add the Griffith’s Gnat for surface work. Once you’ve mastered those three, expand into the specialized patterns for specific conditions.

Midges hatch year-round on virtually every trout stream in the West. Master these tiny flies, keep an eye on flows before you drive, and you’ll never have an off-season again.