Midge For Trout

Photo: Greg Mcdermid

Where I first learned to fly fish, everyone said, "Big flies catch big fish," and that was true. But where I fish now — on tough, technical tailwater trout fisheries like the San Juan, Green, and Frying Pan Rivers — big flies catch mostly stupid little trout.

There are times on some of these tailwaters, most often during the summer, when trout feed on "normal" fare like caddis, mayflies, and sometimes even large terrestrials. But in most of these fertile, dam-released rivers, the vast majority of the aquatic insect population is made up of "midges" — tiny two-winged flies of the order Diptera, of which there are more than 100 species in North America.

Trout feast on these midges all year long, and in the late fall, winter, and early spring, they feed on them almost exclusively. These circumstances require special tactics and tiny flies that imitate the prevalent midge population. I consider these tailwater midge hatches to be one of fly-fishing's highest plateaus To sight-fish to enormous trout with tiny flies and gossamer tippets is a true test of your angling mettle.

Midge Patterns

To be a proficient midge fisherman, you need a range of fly patterns that imitate every stage trout prey upon. You need to know what fly to use, and when to use it. Things can change suddenly during a midge hatch, or combined midge hatches, especially on productive water where large trout have the luxury of targeting specific stages of specific insects. Sometimes you'll tear up the river on a #20 red larva imitation, and then suddenly the fish switch to dark brown #24 pupa. If you can't recognize and make the change, the fish will get the better of you.

Midge larvae. Even the best anglers sometimes overlook the importance of midge larvae. Midge larvae are long and slender with a uniform profile. The best imitations are nothing more than thread — twisted to create a segmented look — wrapped on a curved hook. Andy Kim's Yong Blood [For tying Andy Kim's midge patterns see Fly Tier's Bench in this issue. The Editor.] and Bear Goode's Sparkle Larva are the best examples of these types of patterns. Anything with a bead or with a pronounced thorax has the wrong profile. Take a seine or net with you and match your pattern to the specimens in the stream.

Midge pupae. Think long and slender for midge larvae, short and squat for midge pupae. The pupa's thick thorax contains the adult's developing wings. My favorite pupa imitation is Andy Kim's Yong Special, because it's the closest replication of the originals I see most often on the San Juan, Green, Frying Pan, and other rivers. Old classics such as the Black Beauty, Miracle Nymph, or Brassie work as well. On the Colorado River at Lees Ferry, the Beadhead Zebra Midge is the ticket, especially out in deeper water.

Emerging pupae. When midges begin to emerge, their budding wings become prominent, and they sometimes carry gas bubbles that trigger trout to feed. This phase of the transformation has been studied extensively by some very good anglers who have developed deadly imitations. Rim Chung's RS2 pattern was developed for finicky South Platte trout and has been widely adapted on the San Juan and elsewhere. The WD-40 is an emerging-midge pattern developed by John Engler on the Frying Pan, but it works almost anywhere there are midges. Johnny Gomez's Johnny Flash has the profile of the WD-40 and the emerging wing of the RS2.

Single adult. As with all midge fishing, fly size is the critical element, followed by the shape and color — in that order. There are many excellent patterns out there to choose from. I have had good success with just a thread-body fly with two turns of grizzly hackle. That's all I can tie in a #24 or smaller. My friend Rick Takahashi ties a fly biot midge that is simply sinister to trout, and I swipe as many as I can out of his fly box when he is not looking.


The best midge fishermen have great powers of observation and a meticulous, predatory approach to their angling. Andy Yong Kim — a guide on the San Juan River — is one of these trout hunters. Kim is either changing flies, adjusting weight, changing his leader length, or landing a fish. There is very little wasted effort or fruitless casting involved in his technique. He believes far too many fishermen string their rods at the parking lot and cast the same nymph rigs all day long. They may enjoy some success during parts of the day, but they would catch more fish if they modified their tactics as conditions changed.

If you are serious about fishing midge hatches, your first course of action will be to sample what's in the water with a seine or a small aquarium net. Early in the day, you are likely to see more midge larvae than anything else.

Most of the time, trout feed on midge larvae near the bottom, so you need a nymph rig that delivers the fly to the fish effectively. If you want your fly right on the bottom, the distance between your strike indicator and terminal fly should be about 11/2 times the depth of the water. I think everyone but the most novice angler has heard this advice, but most people refuse to act on it. They still set up a 9-foot leader in the morning and fish with it all day just because it's convenient. That's fine if you are out for the fresh air, but if you want to make every cast count, you must alter your leader to suit specific water depths.

I recommend a moveable yarn indicator or a small cork or foam indicator held in place with a toothpick. Putty, stick-on foam indicators, or loose yarn tied on with a slip knot are fine for static fishing, but can be frustrating nuisances when you move your indicator thirty times a day or more. An indicator that moves quickly and stays in place after you move it will make your day more enjoyable.

The other key to getting your fly to the fish is weight on the leader. Midge flies are too small to effectively use internal weight, so you must carry a good selection of micro-split-shot in various sizes. As with the leader length, you must constantly change the weight on your leader to match the water depth and speed you are fishing in.

Weight on your leader helps you get down to where the fish are, but it also interferes with your ability to detect strikes because it creates a dead zone between the weight and the rest of your leader. Lighter weights reduce this effect, so I recommend using as little weight as possible for the water type. Spreading the weight along the leader also reduces the "anchor" effect. If you need a lot of weight, it's best to distribute a few pieces along the leader, rather than putting on one big shot in a single spot. I fish two flies and always position the top fly above the weight so I have direct contact with at least one fly.

Heavy weight gets your flies down to fish in fast water but can also act like an anchor, creating undetectable subsurface drag. Outfitter and local expert Tim Heng showed me how to defeat this type of drag on the Frying Pan River. My friend and I showed Heng a trout we had spent hours trying to catch, and he promptly hooked and landed the 12-pound leviathan in three casts. He used similar weight to get the fly down to the level of the fish, but when his fly was about 12 or 18 inches in front of the fish, he "hopped" the weight off the river bottom, creating slack in his tippet between the weight and the fly. That's all it took for the trout to inhale his #20 red midge larva imitation.

In a two-fly rig, I tie a pupa on top, because the real thing is likely to be higher in the water column than a larva. When fish begin to key on pupae, they start taking the top fly more than the bottom fly, but there are other signs. You'll begin to see adult midges on the surface of the water and rocks along the shore. If you are sight-fishing, you'll notice the fish are more active. They'll move side to side more frequently, gulping pupae bound for the surface, and they'll often move into different water types to take advantage of the hatch.

When a hatch really gets going, trout suspend in the water column, sometimes just inches under the surface, and gorge on emerging pupae. It's important to pay attention to where the fish are feeding, and if the fish are "up" on midges, you'll have to drastically reduce your leader length. You can do this by moving your strike indicator down the leader toward the fly or by removing the indicator altogether and greasing your leader down to within 12 to 18 inches of the fly.

Photo: Ted Fauceglia

You're likely to see fish breaking the surface when the fish are suspended and eating midge pupae. Many people are fooled when they see this behavior and switch to a dry fly too early in the game. If the hatch is just getting under way, these trout are almost always taking midge pupae just under the surface. You may put on a dry fly and catch a trout or two, or you can fish a midge pupa just under the surface and catch a dozen — it's up to you.

Fish an emerging midge pupa like an invisible dry fly. Grease the leader and tippet down to within a foot of the fly, and you should be able to see the tippet on the water. If your cast turned over correctly, your fly should be about 12 inches beyond the visible portion of your tippet. When a trout makes a grab in this zone, set the hook.

Trout have less time to inspect your fly pattern when they feed close to the surface, but the fishing is rarely easy. Many anglers get frustrated when they aren't getting any takes and often wonder if they have the right pattern or if micro-drag is causing refusals. Sometimes this is the case, but in most instances, the trout has not seen the fly. A trout hanging just inches below the surface has a very narrow field of vision, and in some instances, a fly delivered inches to one side or the other is off target. You have to spoon-feed these trout so all they have to do is open their mouths.

For this reason, long drifts to specific fish are ineffective. You simply can't cast 10 feet upstream of a trout and hope the fly drifts directly to him. Bull's-eye casts are what separate expert midge fishermen from the tourists on tough tailwaters.

The best presentation is usually a down-and-across cast where you deliver the fly 6 inches directly upstream of the trout. You don't need a lot of slack in the line because your drift will be short. For those of us who can't deliver the fly with that degree of accuracy every cast, it's also effective to overcast just a little, pull the fly into the trout's feeding lane, and then drop the rod tip for a short but deadly drift.

Late in the hatch — when pupae begin to dwindle and many adults gather on the surface — trout begin to key on adults. The Griffith's Gnat has caught trout in these situations for decades and is probably the only midge pattern you can see on the water at any distance, which accounts for its great popularity with guides and their sports. Sometimes when midges hatch, they ball up in a clump on the surface of the water. When trout are taking these clumps, the Griffith's Gnat is the perfect imitation.

When midges are not balling up and trout are selectively feeding on tiny individual insects (which is most of the time), it's time for a more realistic imitation. A Griffith's Gnat will take some fish, but the right single adult midge pattern — with the proper presentation — will catch every fish.

A #22-#28 dry fly is impossible for me to see on the water, so I rarely even look for it. I fish the "invisible dry-fly method" I discussed above and concentrate on where the fly ought to be. A greased leader points in the direction of the fly, and after a while you'll find yourself becoming proficient at estimating the distance, and therefore the location, of your fly. Wait until the trout closes its mouth around your fly, and set the hook quickly and delicately.


Small flies, clear water, and wary trout dictate the use of extremely fine tippets. Heavy tippet is not only more visible to the fish, but it is also stiffer and affects the action of the fly in the water. Most successful anglers use 6X tippet or smaller. Dropping to 7X will almost always increase your hookups, and decrease the number of fish you land. I shy away from 7X because I hate to leave hooks in fish and like to land them as quickly as possible. However, if the water is cold and you know how to pressure a fish without breaking your tippet, then there's nothing wrong with dropping to 7X in some instances.

Many of the best tailwater anglers use fluorocarbon tippet almost exclusively for their subsurface fishing, and swear they catch more fish with it than with monofilament. It is a scientific fact that fluorocarbon has a light refraction index close to that of water, which is supposed to make your leader "invisible" to fish. However, when I put fluorocarbon in water, I can still see it, and since it's stiffer than mono, I'm convinced it's more likely to impede the natural action of my fly. Fluorocarbon sinks and should not be used for dry-fly or surface fishing.

In a two-fly rig, your flies should be connected eye to eye with a piece of 12- to 18-inch tippet. Most midge pupae ride the currents in a horizontal position, so your top hook should stick out at a 90-degree angle when the leader is pulled taut. I use improved clinch knots on the top fly because of the small knot size. There are stronger knots, but you usually have to pass the tippet through the eye of the hook twice, and that's not practical on a #24 midge pupa.

Try attaching the bottom fly with a non-slip loop knot. [See "Knots 101," by Lefty Kreh, in our May 2001 issue. The Editor.] The loop knot allows your bottom fly to move more freely in the current regardless of tippet diameter or stiffness.

Your rod choice will vary with the river you are fishing, the wind conditions, and water levels. On a big river like the Colorado at Lees Ferry or the Green River in spring, you'll want a 9-foot, 5-weight to reach distant water and control your line properly. On smaller rivers like the San Juan, Frying Pan, and South Platte, a shorter, 3- or 4-weight is adequate most of the time.

A good reel with a smooth, dependable drag is an asset. I've seen anglers who had to pay out line from their reel manually, because every time a fish hit the reel, it would break off their 7X tippet.

Most of my midge-fishing knowledge I learned from the people I consider to be the real experts on some of the most highly pressured waters in the Rocky Mountain West, but this information is effective everywhere there are midges and trout. The life cycle and presentation tactics I've covered here are universally applicable, but midges come in different sizes and different colors on different waters, so you may have to modify the patterns I've mentioned to match the local hatch. Pay attention to the insects in the water, both where they are and what they look like, and you will be rewarded. Nothing is more satisfying than using your deductive powers to "figure out" a hatch. When you reach that point, you've become more than just a confused bystander hoping to get lucky. You become an understanding participant in a complex ecosystem, and I guarantee you'll have more fun.

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