A few Mays ago I stood in a cold seam below Cheesman with a box full of clever flies and no idea which mayfly the fish were eating. I changed flies four times. The fish ignored all four. Then I tied on a #18 Pheasant Tail — the most boring fly I own — and the next drift came tight.
That’s the whole pitch. When you can’t tell a Baetis from a PMD and the trout aren’t telling you either, one slim brown nymph splits the difference well enough to put you back in the game.
The short answer
The Pheasant Tail is a slim brown mayfly nymph that reads as a Baetis or PMD — for everyday Colorado tailwater fishing run the beadhead version, start at a #18 on water like the South Platte, and drop to #20 or #22 as fish get picky; size up to #16 on freestone. On pressured tailwaters the flashback outfishes the original, and the jig-hook version is the smarter dropper on a euro rig. Match size before you fuss over color — that’s the whole game.
The Original Sawyer Pattern — What It Actually Is
Frank Sawyer tied this fly in England in the 1950s on the River Avon. No thread. No tying silk. Just pheasant tail fibers and fine copper wire — the wire serves as both rib and thread, building the body while adding just enough weight to sink it. The result is a slim, segmented, dark-brown nymph with a copper glint that reads as Baetis, PMD, BWO, or a half-dozen other mayfly nymphs depending on where you fish it.
Sawyer’s original was tied in the #14–#16 range for English chalk stream fish, but the pattern scales perfectly. The whole thing works because there’s nothing to it. Pheasant tail fibers are naturally segmented, they have a brown-reddish tone that matches oxidized nymph coloration almost exactly, and they get slightly translucent when wet — which means a fish looking up at one in a current seam sees something that looks alive. I have tied flies with six materials and a wing I was proud of. The fish ate the four-ingredient one. I’ve stopped taking it personally.
The recipe hasn’t changed much:
- Hook: Standard nymph, #14–#22 depending on water
- Thread: None in the original (copper wire serves this function)
- Tail: 3–4 pheasant tail fibers
- Body: Pheasant tail fibers wrapped forward over copper wire underbody
- Rib: Fine copper wire
- Wingcase: Pheasant tail fibers pulled over the thorax
- Thorax: Pheasant tail fibers, slightly thicker than the abdomen
- Legs: Tips of the wingcase fibers, divided
That’s the whole fly. Strip it down to those components and you understand why it works everywhere.
The Beadhead Version — What Changed and Why
American tiers added the beadhead a few decades back, and it stuck for good reason. The bead does two things: it gets the fly down faster without split shot, and it adds a hot spot just behind the eye that trout key on as a trigger. Gold tungsten reads as a bubble or an emerging nymph’s developing eye cluster. It’s not a stretch — fish eat it because it looks right.
On Colorado tailwaters specifically, I run the beadhead version as my standard Pheasant Tail. The water below Cheesman and through Deckers is cold and clear and moving, and without a bead you’re fighting the current for depth. A 2.5mm or 2.8mm gold slotted tungsten bead on a #18 gets to the bottom seam in reasonable current without stacking a bunch of shot on the leader.
The American beadhead version also typically runs a thread body rather than strict pheasant-fiber-over-wire, which makes it faster to tie and slightly more durable. Both work. The Sawyer original is a slightly slimmer profile and sinks a touch slower — when fish are really pressured, that can matter. For everyday Colorado tailwater nymphing, the beadhead is the one I reach for. The original lives in the box for the days the fish have a PhD.
Size Selection — This Is Where Most Anglers Get It Wrong
Size is the most important variable with the Pheasant Tail. Color matters. Hook gap matters. But get the size wrong and none of the rest of it saves you.
I have stood in a run swapping colors for twenty minutes, certain the fish wanted something warmer, when the actual problem was that my #16 was twice the size of the naturals coming off. When in doubt, go smaller before you go fancier.
| Water Type | Target Bugs | PT Size Range |
|---|---|---|
| Tailwaters (South Platte, Arkansas at Pueblo) | BWO (Baetis spp.), PMD (Ephemerella spp.) | #18–#22 |
| Spring Creeks | PMD, Sulphur, small BWO | #16–#20 |
| Freestone (Rocky Mountain general) | Ephemerella spp., March Brown, larger Baetis | #16 |
| High-altitude lakes/streams | Various small mayflies | #16–#18 |
The biology drives this. Baetis nymphs — the bugs behind BWO hatches — are tiny. On the South Platte, they’re running #20–#22 most of the season. Ephemerella species (PMDs, Pale Evening Duns) are slightly larger, generally #16–#18 on tailwaters, #14–#16 on freestone where the bugs grow bigger in richer, oxygenated water.
May is when both of these hatches converge. BWOs are happening on cloudy days, overcast mornings, or when a weather system rolls through and drops the light. PMDs start coming off mid-morning as the water warms slightly above the early-season cold. Bumping from a #18 PT down to a #20 or #22 as fish get picky later in the day is a normal spring adjustment on Colorado tailwaters.
On freestone streams — the Arkansas above Pueblo Reservoir, the Roaring Fork, upper stretches of the Fryingpan before it becomes the tailwater fishery below Ruedi — you can go a touch bigger. A #16 PT is a legitimate pattern there because the bugs really are larger in those richer, more oxygenated environments. That said, #16 is my floor on a Pheasant Tail anywhere. Below that I’ve got better small-mayfly imitations, and tying a #22 PT is a test of patience I usually fail.
What size Pheasant Tail should I fish in Colorado?
On Colorado tailwaters like the South Platte, start with a #18 and drop to #20 or #22 as fish get picky and the naturals shrink — that range covers BWOs and PMDs. On freestone water, where bugs run larger, a #16 is the call. Match size before color.
Flashback and Jig-Hook Variations — What’s Taken Over Tailwater Fishing
The Flashback Pheasant Tail showed up decades ago and hasn’t left. The concept is simple: a strip of pearl or holographic flashabou or Mylar over the wingcase. When a nymph ascends through the water column, it traps a gas bubble under the developing wingcase — you can see it glinting if you watch real bugs in shallow water. The flash replicates that trigger point and it works.
On heavily pressured tailwaters, the flashback version regularly outperforms the original. Fish that have seen ten thousand standard PTs will eat a flashback because the wingcase flash reads as something slightly different, slightly more alive. My go-to sizes on the South Platte: #18 and #20, 2.5mm gold bead, pearl flash wingcase.
The jig hook conversion is the bigger evolution. Tying a PT on a 60-degree jig hook with a slotted tungsten bead changes the physics of the fly entirely. It rides hook-point-up, which means it tracks through rocky, rubble-bottom runs with dramatically fewer snags. It also rotates into the upper jaw on the take — better hookups in fast water.
The jig PT is now my standard dropper on euro rigs. The Frenchie — essentially a PT abdomen on a jig hook with a hot-spot dubbing collar (UV pink or orange ice dub) behind the bead — sits right in this category. It’s the PT reduced to its most functional form: pheasant tail body, hot spot, jig posture. If I had to fish one PT variant on Deckers for a week straight, the Frenchie in #18 would be a serious contender. (My actual desert-island anchor is the Olsen’s Blowtorch — Devin Olsen’s variant, orange tag for stained water, green for clear — but that’s a hot-spot attractor, not a mayfly imitation, so it’s a different tool for a different job.)
My take
The Pheasant Tail is the fly I trust when I can’t tell which mayfly the fish are on — one slim brown nymph splits the difference between a Baetis and a PMD well enough that I’ve stopped agonizing over the call. That’s worth more than it sounds: half of May is fish eating something mayfly-shaped and me not knowing which, and the PT makes not-knowing a fishable position. Other patterns audition for box space every season. This one’s tenured. Seventy years of trout agreeing with you is a good enough reason to stop overthinking a fly.
How to Fish the Pheasant Tail Under an Indicator
Everybody wants to euro these days, but the bobber still catches fish — especially in May when flows bounce around and trout are spread across a bunch of depth zones. Here’s how I run it.
Set the indicator so your flies are drifting at roughly 1.5x the water depth. If you’re in 3-foot water, set the indicator 4–5 feet from your top fly. Adjust shallower as you move into riffles, deeper as you drop into pools. If you’re not occasionally ticking bottom, you’re fishing the water above the fish.
Two-fly rig: PT on the point (bottom fly), something smaller and midge-ish on the dropper 12–18 inches above it. The PT nymph sinks to the strike zone; the dropper swing-fishes or dead-drifts in the mid-column. On spring days when PMD nymphs are active and fish are feeding mid-water before the hatch kicks off, this setup covers the bases.
Weight placement: one small split shot 6–8 inches above the top fly, not stacked on the leader. You want the rig to tick along the bottom, not drag across it. Tungsten bead on the PT provides much of the sinking weight — the shot just helps anchor the drift.
Strike detection under an indicator is simple: anything that hesitates, ticks, dips, or moves against the current is a fish or the bottom. Set on anything suspicious. Yes, you’ll set on a lot of rocks. Setting on rocks is free; the take you let drift by is not. May PMD nymph takes are often slow and subtle — they’re not smashing it, they’re sipping it in the current.
How to Fish It in a Euro Nymph Rig
This is where the jig PT earns its keep. Euro nymphing puts your flies on the bottom faster and keeps them there longer than any other approach in moving water. For the Pheasant Tail specifically, I fish it one of two ways in a euro setup:
As the dropper: Run a heavier anchor fly (Blowtorch, Duracell, or heavy tungsten bead jig) on the point, PT on the dropper 8–12 inches above. The anchor gets you down; the PT swings and drifts naturally in the current above the bottom. This is a productive combination in May when fish are eating both attractor and imitative patterns.
As the point fly: When fish are specifically keying on mayfly nymphs and rejecting attractor patterns, move the PT to the point and run something smaller — a #22 midge pupa or a soft-hackle — on the dropper. Keep the tippet to 5X or 6X depending on clarity.
Depth control with a PT on a euro rig is about bead sizing. A 2.0mm bead on a #20 PT barely gets you down in faster water — fine for softer seams and flatter runs. Step up to 2.5mm or 2.8mm for heavier current. The sighter on the euro leader is your feedback mechanism: if you’re not occasionally bumping bottom with the anchor, you’re too light or too shallow.
Dry-Dropper Rigs With a Pheasant Tail
May is prime dry-dropper season because PMDs are legitimately hatching and fish are actively looking up. The dry-dropper rig with a PT covers the window right before the hatch peaks — fish that are moving toward the surface but haven’t committed to the dry yet will eat the nymph just below it.
Setup: a #14 or #16 Elk Hair Caddis or PMD Comparadun as the dry, 18–24 inches of 5X fluorocarbon to a #18 beadhead PT. Fish it in riffled sections where the dry can float without dragging and the PT hangs in the mid-column below. When fish start rising, the dry becomes the target. When they stop, the PT cleans up the subsurface feeders.
The dry also doubles as your strike indicator here. Any unnatural twitch or dip means a take on the PT. Keep it simple — don’t run more than 24 inches of dropper or you lose the ability to land fish cleanly in fast water. I’ve fished a four-foot dropper because I was too lazy to re-tie. I lost the fish and learned the lesson on the same drift.
When the Pheasant Tail Shines: Spring Into Early Summer
PMD (Ephemerella dorothea and related species) and BWO (Baetis tricaudatus and B. bicaudatus) nymphs are both active in May across most trout water in the country. These bugs don’t just hatch — they migrate toward the surface days before they actually emerge, which means trout are eating drifting nymphs throughout the water column for weeks before the dry-fly hatch gets going.
The Pheasant Tail matches both. It’s not a perfect imitation of either — it’s a convincing approximation of both, which is the entire trick. BWO nymphs are slim, brown-olive, with a segmented abdomen and visible wingcase: that’s a PT. PMD nymphs have a slightly wider thorax and run a touch warmer in color, but a standard copper-ribbed PT in #16–#18 passes inspection on most water. Trout are not entomologists. Neither, on most days, am I — and the PT forgives both of us.
When the hatch is actually happening and fish are in the upper water column, switch to an emerger pattern — a RS2, a Sparkle Dun, or a CDC BWO emerger. But before the hatch, and after it, and on overcast days when activity is spread across the whole day instead of a concentrated window, the PT nymph fished deep is the answer.
Frequently Asked Questions
Q: What size Pheasant Tail Nymph should I use on tailwaters? Size #18–#22 covers most tailwater situations targeting BWOs and PMDs. Start at #18, drop to #20 or #22 if fish are actively refusing or the hatch is made up of very small bugs. On freestone rivers, size up to #16.
Q: What’s the difference between the original Sawyer Pheasant Tail and the beadhead version? The original Sawyer pattern uses no thread — just copper wire and pheasant tail fibers — and sinks slowly with a very slim profile. The beadhead version adds a tungsten bead for faster sinking and a trigger hotspot. The beadhead is the practical everyday choice; the original outperforms it when fish are pressured and keying on exact profile.
Q: What’s a Flashback Pheasant Tail and when does it work better? A Flashback PT replaces the standard wingcase with a strip of pearl or holographic flash. It imitates the gas bubble that forms under a nymph’s wingcase as it prepares to emerge — a visual trigger that matters when fish have seen thousands of standard PTs. It consistently outperforms the original on high-pressure tailwaters.
Q: Can I fish a Pheasant Tail Nymph on a jig hook? Yes, and on rocky-bottom tailwaters a jig hook PT is the smarter choice. The hook rides point-up, reducing snags, and the fly rotates into the upper jaw on the take for better hookups. The Frenchie is the most popular modern version — PT body on a jig hook with a UV hot-spot collar behind the bead.
Bottom line
The Pheasant Tail has been catching trout since Eisenhower was in office, and it’s not going anywhere. It won’t win any beauty contests in the bin next to the flashier stuff, but it’s the fly I tie on when I’ve run out of clever ideas and the fish have run out of patience — which, on a hard spring day, is most of them.
Buy a dozen in #16, #18, and #20 — half flashback, half standard, a few on jig hooks — and you’ve covered most of a Colorado mayfly season in one corner of the box.
Want to put the jig version to work? Here’s how I rig it on the South Platte for euro nymphing.