Guest Blogger: Clay Cunningham, Cody WY, Former National Park Superintendent

Pteronarcy californica stonefly

In the Western waters when the Pteronarcy californica stonefly hatches, the fish abandon any elusiveness they may have possessed. Known as the Salmon Fly, it is one of the largest of the stoneflies. During the hatch if you didn’t see one land on you, you might think it was a bird. In the Yellowstone drainages the hatch can begin from the end of May to early June. This varies throughout the park depending on the water temperature at different elevations of the park. At higher elevations, a close relative of the californica species, the princeps species will hatch later than the californica.

The Salmon fly Pteronarcy californica spend up to three years as a nymph before emerging. During the months prior to the hatch in any one year there are three sizes of nymphs under the water in various stages of development. The nymphs are often the most numerous species in Western rivers and streams. It is wise to have some imitation of these prolific nymphs. After the hatch, there are two sizes that remain until their complete development. Just prior to a hatch, the generation that is about to hatch migrate from their rocky hiding places to shallow water where they eventually crawl out of the water and attach to nearby rocks or vegetation. That is where their husks split open and the wings emerge. It is the clumsy flying egg laying females that fly low over the water or settle on the water and deposit their egg’s while the fish are voraciously feeding.

During the early 1960s, I frequently fished the Allegheny River for Largemouth Bass and Tionesta Creek for trout in Forest County, Pennsylvania. Both of those drainages contain numerous species of stoneflies though none were the Pteronarcy californica. There were, however, other species of Pteronarcy present, but none were anywhere near as large as the Western Salmon fly, Pteronarcy. I collected many of the stoneflies from both drainages to examine closely so I could create a reasonable stonefly nymph. In doing so, I observed that a number of those live nymphs had some color on the underside. The colors were usually tan to light yellow. I tied a nymph that showed that color and I also added a gold tag at the hook bend, which was popular on tied wet flies. At some time in later years I observed that the famous Western Pteronarcy californica nymph also exhibited color and it varied. On the ones I have seen, it was from yellowish/orange to a stronger orange color. That made me recall that the stonefly nymphs I created and used in Forest County years ago worked well. I thought maybe using a holographic tag and showing color on my tied Pteronarcy californica flies would make them more attractive to being taken by trout. I cannot claim the experiment was an unbelievable success, but those colorful examples were rarely refused.

For the picture I didn’t have a size 2 or 4 fly hook. I had to get this large bait hook from a friend. The proper hook would be a size 4, 5x long Mustad R75-79580 or similar hook in size 2 or 4, and 5 or 6x long to represent the third-year generation of Pteronarcy californica. I use hook sizes 6 and 8, 4 or 5 and 6x long to tie smaller/younger nymph pattern.

For readers in the East who want to experiment with stonefly patterns that have a tag and show some color, I used hook sizes from 6 to 10 that were 3 to 5x long. The patterns for the nymphs you see in the picture are:

Pteronarcy californica

Hook: size 2 to 4, 5 to 6x long
Tag: holographic flat tinsel
Weight: .035 and .025 non-toxic wire
Thread: black
Tail: braided damsel butt
Under wrap: wool yarn
Colored floss: yellowish orange
Rib: dark brown vinyl half around
Wing case: thin rubber, Realskins or scud back
Hackle: black
Antenna: hackle stem

Eastern stoneflies

Hook: size 6 to 10, 3 to 6x long
Tag: gold tinsel or silver or holographic
Weight: .035 and .025
Thread: black
Tail: turkey biot
Under wrap: wool yarn
Colored floss: tan or light yellow
Rib: black vinyl half round
Wing case: scud back
Hackle: black
Antenna: hackle stem


  1. I like those files Clay; very nice. I met a fellow fly fisherman awhile back who insisted that trout respond to a fly’s silhouette, and we know that’s true…but it’s not the whole story. Color matters–they seem to be able to discern even subtle differences in hue. Adding (or changing up) colors on a fly is thus often a good strategy to get their attention. Your stoneflies seem to make use of both attributes. I also notice how the soft hackle is tied almost Tenkara-like–forward, I guess so it will move more when stripped in.

  2. Thanks Mike. Right you are about the hackle. proven to myself years ago that this type of tying on nymphs is more effective in attracting a strike as the simulated legs move a lot more which is more like actual live specimens.

    1. Hi Clay, I haven’t tried the forward-swept hackle approach–I guess I should. I do try to keep my soft hackle standing well out from the hook shank, and that has made a positive difference for me.

      I like to tie soft-hackle wet flies “in the round” so to speak, and I tend to keep the soft hackles pretty long compared to how most other tiers size them, although I don’t know if “too long” hurts my odds or not. I just tend to do it…I have this idea that long soft hackle waving in the current is an attention-getter. But I don’t actually know if it makes the fly look more like food, or less. Maybe I should try ganging two flies together–one with long hackle and one without.

      – Mike

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