IS COLOR IMPORTANT? This is a serious question for fly tiers and fly fishermen to ask. Some anglers maintain that the choice of color is critical, while others say it is not important. Scientifically speaking, there is evidence to suggest that both points of view may be correct. There is good evidence that picking the appropriate color or colors will, under certain conditions, improve your chances of attracting fish, but science can also show that in other situations, the color of your fly is of limited value or no importance whatsoever.

Fish have been around for more than 450 million years and are remarkable creatures. Over the thousands of centuries, they have made many superb adaptations to survive in the marine environment. Living in the world of water is not easy, but it does present some environmental opportunities as well as serious challenges. Sound, for example, travels almost five times faster and much better in water than it does in air. The ocean is actually a very noisy place. Fish capitalize on this by having an excellent sense of hearing, using both their inner ears and lateral lines to detect prey or avoid enemies.

Water also contains unique chemical compounds that fish utilize to identify other members of their species, tell when reproduction time has arrived, find food, detect predators, and perform other functions. Fish have evolved a remarkable sense of smell that is thought to be about one million times better than that of humans.

Water, however, presents a serious challenge for fish and fishermen when it comes to vision and color. Many characteristics of light quickly change as it moves through water. The first thing to realize is that the color of your fly in the water is almost always different from what it is in the air. I have to be a little technical to explain this, but I think if you bear with me, you'll have a better understanding of how fish perceive color and how this impacts the flies we tie and use. And while I mostly refer to fish and fishing in salt water, these same principles apply to the freshwater environment.

Attenuation of Light

The light that humans see is just a small part of the total electromagnetic radiation that is received from the sun. We see what is called the visible spectrum. The actual colors within the visible spectrum are determined by the wavelengths of the light: the longer wavelengths are red and orange; the shorter wavelengths are green, blue, and violet. Many fish, however, can see colors that we do not, including ultraviolet.

When light enters water, its intensity quickly decreases and its color changes. These changes are called attenuation. Attenuation is the result of two processes: scattering and absorption. The scattering of light is caused by particles or other small objects suspended in the water — the more the particles, the more the scattering. The scattering of light in water is somewhat similar to the effect of smoke or fog in the atmosphere. Coastal waters generally have more suspended material due to river input, material stirred up from the bottom, and increased plankton. Because of this greater amount of suspended material, light usually penetrates to a lesser depth. In relatively clear offshore water, light penetrates to a greater depth.

Light absorption is caused by several things, such as the light being converted into heat or used in chemical reactions such as photosynthesis. The most important aspect for fishing is the influence of the water itself on the absorption of light. The amount of absorption is different for different wavelengths of light; in other words, various colors are absorbed differently. The longer wavelengths, such as red and orange, are absorbed very quickly and penetrate into the water to a much shallower depth than the shorter blue and violet wavelengths.

Feather Pup

Hook: Regular saltwater hook, size 3/0.
Thread: Brown Monocord (210 denier).
Wing: Brown bucktail with strands of gold Flashabou. Tie two brown grizzly hackles and one golden brown grizzly hackle on each side of the tail. Tie the hackles curving out.
Collar: Brown marabou.
Head: Brown Wool.
Eyes: Yellow plastic doll eyes.

Tied by Capt. Lenny Moffo, Big Pine Key, Florida

Absorption also restricts how far light penetrates into the water. At about three meters (about 10 feet), roughly 60 percent of the total light (sunlight or moonlight) and almost all the red light will be absorbed. At 10 meters (about 33 feet), about 85 percent of the total light and all the red, orange, and yellow light have been absorbed. This has a direct bearing on how a fish perceives a fly. At a depth of 10 feet, a red fly appears gray, and it eventually appears black as the depth increases. With the increasing depth, the now dimming light becomes bluish and eventually black when all the other colors are absorbed.

The absorption or filtering out of color also works in a horizontal direction. So again, a red fly that is only a few feet from a fish appears gray. Similarly, other colors also change with distance. For a color to be seen, it must be hit by light of the same color and then reflected in the direction of the fish. If the water has already attenuated or filtered out) a color, that color will appear gray or black. (Fluorescent colors, which I will come to shortly, behave a little differently.)

It should now be clear how the depth of the water or distance from a fish affects the visibility of your fly. In extremely shallow and very clear water, colors may look similar to their appearance in the air; as your fly gets just three feet deep or three feet away from a fish — or less if the water has limited clarity — the colors will start to change, often with surprising results.

What Do Fish See?

Scientists really do not know exactly what fish see, or in other words, what images reach their brains. Most research on the vision of fish is done either by physical or chemical examination of different parts of their eyes or by determining how laboratory fish respond to various images or stimuli. Making broad generalizations about a fish's vision is complicated by the fact that different species may have different vision capabilities and that laboratory results may not represent what happens in the real world of an ocean, lake, or river.

Physical studies of the eyes and retinas of fish show that the majority can obtain a clearly focused image, detect motion, and have good contrast-detection ability. A limited number of experiments have shown that a minimum level of light is necessary before a fish can recognize colors. Another finding, but one that needs more study, is that some fish favor a specific color. This point may contradict or affirm your own fishing experiences, but remember that the attractiveness of your fly is a combination of many things, including its motion, shape, and color, as well as the scents in and depth of the water.

Most fish have an adequate sense of vision, but this is usually not so impressive as their sense of smell and ability to detect vibrations through their lateral lines. Fish usually use their sense of hearing or smell to initially perceive their prey, and then use their vision only in the final attack. Most fish can see in low-light conditions or dirty water, and a few can see objects over moderately long distances. Fish such as tuna have especially good vision; others less so. Fish are usually nearsighted, although it is believed that sharks are farsighted.

The majority of fish have developed eyes that will detect the type of colors typical of their environment. For example, inshore fish have good color vision, whereas offshore pelagic fish have limited color vision and detect only a few if any colors other than black and white. This is not surprising from an evolutionary point of view, because nearshore waters are lit with many colors; offshore waters, on the other hand, are mainly blue or green and contain few other colors.

The actual ability of a specific color to attract or even repel fish has fascinated both anglers and scientists. While there are no uniform answers, scientists have conducted experiments on this interesting question. For example, studies of sticklebacks during their spawning season have shown that males, which then have bright red coloring on their bellies, become very aggressive to decoys that also have bright red bellies. Similarly, decoys with extended bellies, which look like females carrying eggs, attract the males. But it isn't that simple: it wasn't just the case of a perfect decoy imitation, but rather the color or shape of the decoy. In addition, it was noted that a passing red car, seen from the fish tank, also excited male sticklebacks.

Continue Reading "Does Color Matter?"      1   2

Dr. David Ross is a senior scientist emeritus at the Woods Hole Oceanographic Institution and the author of The Fisherman’s Ocean (Stackpole Books). He can be contacted at DRoss@whoi.edu. This article first appeared in Fly Tyer Magazine. © 2005-2006 Dr. David A. Ross and Fly Tyer Magazine.

The flies appearing in this article are from the book Tying Contemporary Saltwater Flies by David Klausmeyer (Countryman Press, 2002, 160 pages).