dry fly patterns
Trout Flies

Designing Trout Flies for Better Fishing

I must confess that I don’t really love to tie bunches of trout flies. I just can’t seem to strap myself to the fly tying bench in winter-time to do so. In fact, I tie most of my flies in proximetry to a fishing trip. Other times, it’s when I find a new tying material, learn of a new or different technique, or think I may have stumbled upon something new myself. I’m always tying and designing trout flies for better fishing, or at least that’s the plan.

Although I have my “own” collection of fly patterns, as discussed in our book The Ramblings of an Aging Angler, it is doubtful that any of us really creates a completely new fly pattern. This is hardly surprising, given the thousands of patterns that already exist, many of which have been created, tied and fished for centuries. Rather, we make useful modifications to an existing pattern.  We may substitute new materials, or add/subtract wings, legs, tails or shucks. All in an effort to better address the conditions on the streams that we fish most often.

Historical Notes

We know from the fly fishing literature, that fly fishers have been tying flies for at least two millennia. The first pattern was described by a Roman naturalist, Claudius Aelianus, about two hundred A.D. Twelve patterns were next described in “The Treatyse of Fysshynge Wyth an Angle”, thought to be written in 1450 by Dame Juliana Berners. At that time, and for several centuries to follow, it was a necessity to tie one’s own flies. Fly shops and commercial tiers didn’t exist as they do today. Now of course, we can buy flies easily, and more cheaply, than we can tie them ourselves. Yet many, if not most, fly fishers continue to tie their own, including myself.

I don’t fully understand why I tie flies. However, I suspect that just as we wade into the watery world of the trout to better study and understand it, that tying flies affords the opportunity to better understand why some flies “work” better than others. That is, why a fly catches more trout, the primary goal of this exercise for most of us.

An understanding of the concepts of a “good” fly assists anyone who ties flies. It also helps anyone who ventures into a fly shop, glances at the hundreds of bins overflowing with flies, and tries to select a few for a productive day’s fishing.

The important attributes of a good fly have not changed over time. However, their relative importance has been and continues to be debated. I am not going to enter into a discourse of this centuries old debate. But I am going to exercise a writer’s prerogative at times, and express my own, personal opinion, which will of necessity be at odds with some, or there would be no debate. But from debate comes learning! Perhaps this article will prompt some replies in our forum.

The three basic elements of a fly are of course its size, shape or form, and color. Another important element when fished is its behavior, or its ability to look alive. The materials used in making the fly, and how they are arranged or attached, affect the ability of the fly to appear lively. This is especially true when fishing subsurface flies. These four elements then, should be carefully considered in the crafting of every fly.

Dry Flies

Let’s first consider the floating or dry fly. I believe that size is of primal importance, especially when fishing quiet waters such as tailwaters, spring creeks and stillwaters. In these types of water, trout have the luxury to closely inspect our imitations, and if they are oversized, they are invariably refused, that is, rejected. Most fly fishers overestimate the size of the natural flies they are trying to imitate. This is perhaps due to the flies’ prominent wings, which are a size and a half larger than the body of the fly. With the exception of drakes and stoneflies, most aquatic insect bodies are size #16 or less.

Within any given hatch, there will be some variation in the size of the hatching flies. Thus, fishing an artificial fly a bit smaller than the largest specimens that we see on the water will not deter the trout from taking it. The opposite is usually the case when fishing an oversized fly.

When fishing freestone streams, especially sections of rougher water, size becomes a bit less important. In such water, trout don’t usually have the same luxury of closely inspecting the fly. In addition, the turbulence of the water undoubtedly distorts the image of the fly as well. Thus larger, bushier flies can be used, which helps keep them afloat and makes them more visible to the fly fisher.

Next in importance is the shape or form of the fly. Classic Catskill-style flies will catch trout, but it has been my experience that other styles are far more productive. The Catskill fly nicely imitates a fly about to leave the surface of the water, that is, to fly away. Consequently, a waiting trout has but a second or two to make its move and ingest the fly. A near miss represents a loss of energy, something a trout can ill afford to do with any frequency. Therefore, trout will preferentially feed on more vulnerable flies, such as cripples struggling to escape their nymphal shucks, stillborns and spinners. Thus, flush-floating patterns that imitate these flies will be far more productive. Commonly used patterns include comparaduns, parachutes, spinners and cripples.

top: Catskill style flies bottom: comparadun, parachute & spinner flies
top: Catskill style flies
bottom: comparadun, parachute & spinner flies

Next is color, which is the most difficult of the three attributes to understand, and probably the least important. Much about the trout’s vision can be deduced from the anatomy of its eye. But we will never know with certainty what a trout actually sees, only that it does not see things as we do. It lives in an aqueous environment, where the penetration of light-rays rapidly diminishes as they pass through the water column. If there is turbidity due to silt or algae, light is further reduced. Hence, a trout’s ocular system is designed to maximize vision in a dimly lit world.

Their eyes lack both an eyelid and reactive iris, both of which could be used to limit the entrance of light into the eye. This may be part of the reason that trout seek shady and/or deep water during much of the brightest portions of the day. In addition, when a trout rises to the water’s surface to capture a bug in bright sunshine, it probably encounters a sunburst effect, such as happens to the human eye. This makes it difficult to see color at all. In contrast, on an overcast day, color is likely to be far more perceptible to the trout, and therefore, the fly fisher’s color selection will be of greater consequence.

Another anatomic difference between the trout and human eye, is the ratio of rods (the receptors most sensitive to light) to cones (the receptors most sensitive to color). Trout have a much greater proportion of rods, enhancing their ability to see in their darker world. But this is at the expense of color perception. This is not to suggest that color plays no role, but it’s role is more complex than we might assume. Certainly, the fly that we see in our fly box, is not the fly that the trout sees.

I do think it is important to use a fly that is a similar shade or tone as the fly that is hatching, that is, light, dark or medium.  But I don’t think it must be the same precise color. How else can one explain the trout’s acceptance of a parachute Adams, the gray color of which matches no native fly, but whose medium tone or shade is similar to many?

If we closely examine a natural fly, it rarely reflects solely one color. In addition, they have chitin in their exoskeletons, giving them a bright reflectance. Thus I prefer to use dubbing blends that have a mix of colors and include a bit of sparkle, such as the Dave Whitlock dubbing blends, one of which is shown below, which incorporate these features.

a Dave Whitlock dubbing blend
a Dave Whitlock dubbing blend

Subsurface Flies

Sunken or wet flies present a different set of challenges. For this discussion I will divide them into two groups, nymphs  and streamers. Size remains important for nymphs. As discussed in my October article, “Fall Fly Fishing- Strategies for Trout“, the size of nymphs changes dramatically over the course of a year, corresponding to the life cycle of aquatic bugs. Most bugs hatch, mate and egg-lay over the summer. In the fall, the new nymphs are small, size #20 or less. They gradually grow over the year, reaching their maximum size just before emerging the following spring and summer. Therefore, fishing the right sized nymph, especially in the fall, will significantly increase the number of hook-ups.

I think that shape also remains important. Nearly twenty years ago, I observed that nymph patterns, attached to a leader, tumble over and over when in the drift. This is not a natural presentation for a living nymph. Therefore, I tie nearly all my nymphs in the round, using hen hackle for a collar, similar to old fashioned wet flies. Tied in this fashion, my nymphs are always seen to be right side up, never upside down. Also, hen hackle provides a great deal of movement or life to my imitations. Over the past decade, I think that many fly fishers have come to the same conclusion, as these patterns are found with increasing frequency in the fly-bins of commercial fly shops.

nymphs tied "in the round"
nymphs tied “in the round”

Last again is color. I use muted colors, generally in shades of olive and brown, mottled, with a bit of flash or fluorescence. I study the color of each stream bottom to guide my selection. Nymphs and larvae live on and within the bottom matter of a streambed, and are usually camouflaged so as to blend in and avoid predation.

With streamers, size is again important. While small streamers will be taken by all sizes of trout, large streamers, five or six inches in length, will not be taken by any but the largest trout. Thus the number and size of your catch will be affected by the size of the streamer you choose to fish.

To give lifelike movement to the fly, it is important to use materials which readily undulate and move in the water. Bunny and marabou are two such materials. I also prefer to use flies with weight in the head. This will impart a dipping motion to the fly when it is brought to a stop, simulating an injured or dying minnow. These are inviting targets for a hungry trout.

The appearance of an artificial fly’s color, as seen by a trout beneath the water’s surface, is very difficult to assess. When an artificial fly becomes wet, most of its colored materials will become darker. As it descends in the water column, there is less light, and longer wavelengths are filtered out. These factors further change the color of the fly, which will appear more monochromatic, that is, gray. Regardless of the color, flies will be seen in varying shades, light, intermediate or dark. I therefore tie various shades of any color streamer I plan to fish, usually shades of tan or olive. Usually I add a bit of flashabou for some sparkle. I fish the lighter shades in shallower water, and the darker shades in deeper water.

These are a few of my thoughts regarding the important elements of tying flies. If interested, the following are excellent books to read as well. But always remember, trout are the best fly-tying instructors!

Designing Trout Flies by Gary Borger

The Dry Fly, New Angles by Gary LaFontaine

Trout Flies, The Tier’s Reference by Dave Hughes

The Fly-Fisher’s Craft, The Art and History by Darrel Martin.

Written by Allan G. Simpson, February 2015.                                      Edited December, 2016.

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