If you've spent time on Colorado's high-altitude stillwaters — Antero, Spinney Mountain, 11 Mile, Delaney Buttes — you've probably watched fish sipping just under the surface while your indicator sat motionless. That's chironomid feeding behavior, and learning to capitalize on it is the single biggest skill upgrade available to stillwater anglers in Colorado.
Chironomids — also called midges or "chiros" — are aquatic insects that live the majority of their life in the mud at the bottom of lakes. Their pupae slowly rise through the water column to hatch at the surface, and trout intercept them at every stage of that rise. In Colorado's alpine and sub-alpine stillwaters, chironomids are available 12 months a year, making them the single most important food source for stillwater trout.
The most effective method for fishing chironomid pupae is the indicator method — suspending your fly at a precise depth beneath a strike indicator. Here's the basic setup:
The most common mistake is fishing too shallow. In Colorado's deep reservoirs like Antero and Spinney, fish often hold in 12–18 feet of water. Don't be afraid to set your indicator deep.
Chironomid hatches happen in the calmer, shallower areas of a lake — usually 6–20 feet deep. Look for flats, edges along drop-offs, and bays protected from the wind. At Antero and Spinney, the red-bottomed areas are rich in chironomid larvae and are prime feeding zones.
In Colorado, the most productive chironomid colors are black, red, olive, and brown — often with a silver or gold rib and a white or glass bead. Size matters more than people think. Start with #14–16, but don't be afraid to drop to #18–20 on pressured water. All Trout Tricks chironomids are tied on 2x heavy wire hooks that won't straighten on trophy fish, with high-quality tungsten beads that get the fly to depth fast.
For clear water and bright days, the Snow Cone — white bead over a slim body — reads like a pupa mid-ascent and outfishes darker patterns by a wide margin. On stained water or overcast mornings, switch to the Chocolate Gold or Burnt Wino — the gold rib picks up what little light is down there. When fish are keying on emergers just under the film, a Chirono'midge fished as the top fly on a dropper is the move. And if pressure is grinding the bite down to nothing, the Winged Duck or Winged Cone from our Top Secret lineup gets refusals to convert — these are the patterns I don't like to tell people about.
Chironomid fishing in Colorado is year-round, but the best fishing typically occurs in spring (March–May) and fall (September–October) when water temps are cooler and trout are actively feeding. Early morning and late evening sessions often produce the most fish, though midday can be excellent when hatches are peaking.
The fastest way to dial in chironomid fishing is on the water with someone who knows these fisheries. Check out our guided stillwater trips — we fish Antero, Spinney, 11 Mile, and Delaney Buttes throughout the season and will put you on fish while teaching you the skills to replicate it on your own.
Recommended reading: our roundup of the best chironomid fly patterns, chironomid fishing on South Park reservoirs, and the #1 mistake stillwater anglers make.
Patterns referenced in this article — every one hand-tied fresh on 2x heavy hooks with tungsten beads:
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