Walk into a fly shop in Pueblo and the bins look subtly different from the ones in Salida. Smaller midges. More scud colors. A Trico section that wouldn’t fit in a freestone shop’s wall space. The best flies for the Pueblo Tailwater aren’t the same patterns that win above Browns Canyon — they’re tuned for cold steady water, a constant food drift, and trout that have been looking at heavy spring-creek hatches for twelve months a year. The box is leaner, smaller, and a size darker than what works upstream.

This is what stays in our boxes for the Pueblo Tailwater section from January through December, organized by what’s hatching and what’s earning real estate.

Year-Round Anchor Patterns

These never come out of the box. If you can only carry six patterns to this water, carry these six.

  • Black Beauty (#20–24): — The default midge larva on this stretch. Slim profile, bead head, fished as the top dropper on almost every nymph rig from October through April.
  • Olive Zebra Midge (#20–22): — When the bite turns soft, this is the swap. Tied with copper wire, the olive body gets eaten when the black version stops getting eaten.
  • Scud, tan or pink (#16–18): — Tailwaters are scud factories. A weighted scud as the point fly drops a lighter midge into the strike zone all year.
  • RS2, gray or olive (#20–22): — The single best emerger pattern on cold tailwater. Fish it dropper under a nymph or dead-drifted in the film during a midge or BWO hatch.
  • Pheasant Tail Nymph (#18–20): — The catch-all mayfly nymph. Earns its keep through BWO, PMD, and Trico cycles.
  • Sparkle Dun, gray or olive (#18–22): — One dry that covers midge clusters, BWO duns, and PMD spinners with a size and color swap.

Six patterns won’t be enough on a tough day. But on most days, four of these six will get bites in the first hour.

Why the Pueblo Tailwater Best Flies Run Smaller

A quick word on size. The single most repeated mistake on this water is bringing the same flies that worked on the upper Arkansas and tying on the same size. The Pueblo Tailwater best flies are almost always one to two sizes smaller than their upstream equivalents. A #16 Elk Hair Caddis that crushed in Salida last weekend will get refused for a #18 here. A #18 BWO Comparadun will lose to a #20. The reason is partly food size — cold tailwater bugs run smaller — and partly fish education. These trout see thousands of drifts a year from skilled anglers; the small fly is the one they haven’t gotten stuck on yet.

The other tuning detail: tippet diameter matters here as much as fly size. Pair a small fly with a tippet that’s too heavy and the drift drag will give it away. 6X fluorocarbon for midges and BWOs, 7X for Tricos, 5X for caddis and PMDs. Tie blood knots, not surgeon’s knots, when you can — the smaller knot profile slides through guides cleaner during a long winter session.

Spring Box: March – May

The story is the midge-to-BWO crossover, with a caddis pop showing up at the very end of May.

  • Top Secret Midge (#20–22): — Midge adult/emerger with a CDC wing. Greased and floated in slow tailout foam lines during late-morning midge windows.
  • Juju Baetis (#18–20): — The standout BWO nymph here. Outproduces a standard Pheasant Tail on overcast afternoons in April.
  • CDC Comparadun, olive (#18–20): — When duns are riding, this is the pattern. Refusal-proof in a way that calf-tail comparaduns aren’t on this pressured water.
  • Elk Hair Caddis (#16): — Late May only. The first Mother’s Day caddis run hits Pueblo a week or two before the upper Arkansas; a single fly carries you through.

For the bigger spring picture — flows, hatch timing, and where to walk — read the full Pueblo Tailwater spring fishing breakdown.

Pueblo Tailwater fly box organized for summer caddis and PMD

Summer Box: June – August

Summer brings warmer afternoons, longer daylight, and the only window when this water sees consistent terrestrial action. Hatches stack: caddis hold, PMDs build through June, Tricos take over in late July.

  • PMD Emerger (#16–18): — Yellow body, sparse CDC wing. The summer mayfly emerger; fish it as a dropper off a dry through mid-morning.
  • Barr’s Graphic Caddis Pupa (#14–16): — The summer caddis nymph. Heavier and brighter than the BWO patterns; gets weight in the rig.
  • Hippie Stomper, tan or purple (#12–14): — The high-vis indicator dry through summer. Add a dropper and it becomes a dry-dropper rig that fishes the same water two ways.
  • Hopper-Dropper combo (#10 foam hopper / #16 nymph): — August. Pueblo doesn’t have the hopper density of Browns Canyon, but the grass edges produce on warm afternoons.

Late-Summer Trico Game

If you’re going to come to the Pueblo Tailwater for one hatch, come for the Tricos. Late July through September the spinner falls happen at 8–9 a.m. on flat tailouts, and the rises last until the sun cooks them out around 10:30.

  • Trico Spinner (#22–24): — Black body, white wing, no hackle. Tied parachute or as a true spinner with spent wings; fish it on 7X fluorocarbon.
  • Trico Comparadun (#22): — For the brief dun window before the spinner fall.
  • Sunken Trico (#22): — The unsung hero. Dropped 6 inches below a small spinner pattern, it picks up fish that won’t commit to the surface.

The Trico fall takes practice — small flies, light tippet, and slow tailout currents that magnify drag. It is also the single best opportunity on this water to land a 17-inch rainbow on a dry fly.

Fall Box: September – November

BWOs come back, browns get aggressive ahead of the spawn, and streamers earn a permanent spot in the box.

  • Juju Baetis (#20): — Same fly as spring, smaller. Fall BWOs run a size or two down from spring.
  • Sparkle Wing RS2 (#22): — The killer emerger when the air turns cold and fish key on cripples.
  • Sculpzilla, olive or black (#6–8): — Brown trout in October are looking for protein. Strip it slow through deep slots in the first mile.
  • Mini Wooly Bugger, olive (#10–12): — The “shouldn’t be on a tailwater” pattern that catches fall browns when the streamer dial is too aggressive.

Keep streamer work to early morning and late evening, and avoid casting at obviously paired-up fish on redds — both ethical practice and Colorado Parks and Wildlife regulations on this stretch protect spawning trout. The conservation work that keeps this water healthy is largely driven by local volunteers; the Pueblo chapter of Trout Unlimited does annual cleanups along the Nature Center stretch and is worth supporting if you fish here regularly.

Wading the Arkansas River below Pueblo Dam, where the Pueblo tailwater best flies run small year-round

Winter Box: December – February

December through February is a midge game with a Baetis chance. Crowds disappear, fish slide into deeper slots, and a quiet midge angler can have miles of water to himself.

  • Black Beauty (#22–24): — The single fly that catches the most winter fish on this water. Tied small, fished slow, bead heavy enough to plant it on the bottom.
  • Mercury Midge (#22): — When the Black Beauty bite slows, the silver bead head adds just enough flash.
  • Disco Midge, red or olive (#22): — Cluster midge dry for the rare midwinter rise on a warm day.

A Note on Sizes

Whatever you tie for the Pueblo Tailwater, tie a size smaller than your gut says. This water is famous for refusing duns that get eaten everywhere else on the Arkansas. A #20 BWO that worked in Salida last week will get refused here in favor of a #22. Carry one box of “regulation size” and one box of “smaller than that” — and on tough days, only open the second one.

Use the Box

Pair this with the Pueblo Tailwater nymphing guide for the rigs that put these flies in the strike zone, and pull up River Conditions in the FlyGuysNLies app before you tie one on. The hatches above are timed for the Pueblo Tailwater section specifically — they’ll shift by a week or two depending on water temperature and release schedule.

Tight lines.

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