By Patrick Straub Explore Big Sky Fishing Columnist

My angling timeline looks like this: Childhood fishing on the Gallatin River; skipping class in high school to float-fish the Mother’s Day caddis hatches on the Madison and Yellowstone; matching hatches on the Paradise Valley Spring Creeks in college; then, discovering the high-stakes game of permit on the fly amidst sun-drenched saltwater flats.

Then I discovered the midge… and an understanding of this oft-misunderstood insect opened up a new world of trout-angling success.

The scene occurs daily here in the fly shop. Anglers come in asking, “What are they biting on?” I walk over to our large fly bins and point-out a few size 18 and 20 midge larvae, pupa, or adult fly patterns.

“How do the fish see those?” is a typical response. I tell them I don’t really care how trout see a tiny fly, all I care about is that they do see it, and then eat it. I sell them some flies, and as they walk out the door I can feel a minor sense of disbelief. They come back within a few hours or the next day all smiles because those darn small flies catch fish.

Many anglers refer to all small flies as midges, but this is a falsity. There are several classes of midges, but trout fishers need only be concerned with bugs in the family Chironomidae. Midges are still very small, however, and are best imitated with flies sized 18 and smaller.

Midges hatch in abundance because of their small size. This translates into many opportunities to get your fly in front of feeding trout. I tell people that trout feed on midges like we do on popcorn – typically in large quantities and rarely eating just one or two pieces in a sitting.

The basics: a midge’s life cycle

Midges have three distinct stages: larval, pupae and adult. During the worm-like larval stage, the midge burrows, crawls, and wiggles. Fish do eat midge larvae, but as the larvae begin to “pupate,” things really get going.
Similar to caddis, a pupating midge rises through the water column to eventually hang just under the surface – easy pickings for trout. When the midge is ready to hatch, or emerge, the insect releases gasses and attempts to free themselves from their pupal shuck. This struggle attracts feeding and rising trout for the attuned angler.

How an angler responds

If you cannot see fish feeding subsurface, a little prospecting offers insight. Start with a two-fly nymph set-up. Use one fly imitating the larval stage – my favorites are the Miracle Nymph and the Halo Midge Larva – and one fly imitating the pupal stage – try a black Zebra Midge or a Don King Midge. If trout are consistently eating one pattern instead of the other, switch to two patterns from the same stage.

When fishing subsurface, I always use fluorocarbon and fish the lightest tippet I can. In winter, I fish 5X and 6X fluorocarbon regularly with the smallest strike indicator possible – often, it’s a small tuft of yarn instead of a plastic bubble. In deeper water, the bubble will come in handy, but by going as small as possible, subtle strikes rarely go undetected.

When trout break the surface they’re feeding on emerging midges or adult midges. Here, use the two-fly tactic again. Fish a high-floating dry-fly midge imitation, either a Buzzball or a Griffith’s Gnat in sizes 18 or 20. From the bend of the hook on the dry fly tie an emerging midge pattern one size smaller than your dry fly. To imitate emerging midges, I use RS2s and CDC Midge Emergers.

But be sure to choose the correct size. I’ve found I rarely fish sizes smaller than 22, but in many cases a size 20 will catch fish when a size 18 will not.

Fishing to trout rising on midges requires a few tackle adjustments. I never use fluorocarbon for fishing small dry flies. I use TroutHunter Finesse or Rio Suppleflex tippets exclusively, and apply a liquid floatant and powder dessicant. The liquid floatant doesn’t goop-up the tiny dry flies, while the dessicant dries and dusts the fly in a hint of white powder, making it easier to detect.

Success with midges

Fishing midges, and fishing them with success, is often overlooked. Fortunately here in Big Sky, opportunities to hone your skills abound. Sure the insects are small and trout rise to midges only during a few hours of the day. And you’re right, threading 5X or 6X on a size 22 isn’t as easy as saving 15 percent or more on car insurance.
But practice gets you closer to perfect and if you can attain a marginal understanding of fishing midge patterns, you will catch more fish.

Pat Straub is the author of six books, including The Frugal Fly Fisher, Montana On The Fly, and Everything You Always Wanted to Know About Fly Fishing. He and his wife own Gallatin River Guides in Big Sky.