Eye of the Guide


Tom Travis - March 14, 2011

To become skilled and successful at fishing dry mayfly imitations the angler must come to understand the behavior of the trout and how the trout will react to any number of natural and unnatural situations that are encountered.

For the past hundred years anglers have had bitter battles over the trout’s ability to see color and if matching the color with our imitations were critical to the angler’s success. In his 1986 book entitled Trout On A Fly", Lee Wulff says:

"Can trout see color? The scientists tell us they can. Do they see color as we do? Ah! That's another question. The chance that trout see color exactly as we do is, I believe extremely slim.'

Personally, I think the whole debate is silly, because until someone interviews a talking trout anything we say is mere speculation. Still, this problem of color has to be handled. I believe that it doesn't matter how trout may see color in relation to how we see color. If we accept the fact that they see color, (and I do) then all we need to do is reproduce the color of the natural as close as possible when tying our imitations and perhaps then the trout will see our imitations as it sees the naturals. Thus we have solved the problem to the best of our abilities and can then move on to other issues.

It seems like at least once each year some would be "Expert" publishes an article on how "simple and easy fly fishing is to learn" or how the angler only  needs these "eight dry flies" to cover all the possibilities. These articles are so much garbage!! I firmly agree with Gary LaFontaine who wrote in his 1990 book entitled The Dry Fly‑-New Angles:

"To attract new converts to fly fishing, instructors keep saying how easy it is to learn. They're only talking about the casting mechanics. In this way they ignore the need for stream awareness, which isn't easy and which can't be taught, only practiced, and they bring their pupils to an acceptable level of mediocrity as quickly as possible."

This fact along with the "Look how easy it is" articles are disgusting. They do a disservice to both the beginner and to those who are learning and progressing as anglers. Sure, learning the basic mechanics of fly-fishing is fairly easy, but there is much more to it than that. I also believe that the angler can take the sport to any level desired and be content. But that doesn't mean that the anglers who choose to pursue and refine their skill levels to the highest degree possible should be scoffed at or that their accomplishments should be disregarded.

There are those that ask "How can you talk about imitations that reproduce the color as close as possible on one hand, and yet support the use of attractors?" OK. That is a fair question. To answer that I will talk about water types, fertile and infertile, smooth versus fast, sight fishing versus covering the water and finally wade fishing or float fishing.


Certain streams are very rich (fertile) in aquatic food forms. They often have very predictable hatches and can even have more than one major species hatching at the same time. These waters tend to be very weedy and often are smooth in nature. During the hatches the angler must have the best imitations possible for the trout are often "choosy" even with the natural insects. During the hatch the angler is generally fishing to visibly rising trout and has to take care in the approach and casting angle used to cover these fish. Even on this type of water I will fish attractor patterns between the hatches looking for feeders of opportunity. In this area we have several streams of this nature such as the Firehole, Henry's Fork, Big Horn, and the spring creeks of Paradise Valley to name a few.


We also fish many streams that may have very few major hatches. Sampling of the bottom shows that the stream is not very rich in varied aquatic food forms. Often these streams have a faster gradient, meaning plenty of riffles and fast moving runs. On this type of water the angler should still use a good imitation if there is a hatch of insects, but often times we see no major hatching activity. Therefore the most productive method to move fish in this type of water is often by covering the water and using attractor type patterns. Remember, the trout's survival depends on energy taken in versus energy spent. Therefore in the faster waters of an infertile stream the trout doesn't have the option of carefully looking over the imitation. The food must be taken quickly or ignored. A good example of this type of water would be the Gallatin River.


On larger western rivers like the Yellowstone the angler will often find that floating is the best way to cover the water. Here again, if there is a major hatch in progress the angler would want to match it. But often times attractor patterns are used to cover the water as the boat floats along.

I would like to mention that while floating the angler should be very observant. Often you can float into a section where there is a hatch in progress. When this situation is encountered, the angler should stop the boat and wade fish to the risers with a pattern that closely imitates the hatching insect. Float fishing and covering the water with attractor patterns is best defined as looking for "feeders of opportunity."

As you can see, what type of imitation you use can depend on the type of water and the conditions under which you are fishing. Once again, one of the major keys to angler success is the ability to observe and respond to that observation in a positive manner.

Those who try to break apart fishing with imitations that represent a specific insect and fishing with attractors are in fact limiting themselves during certain periods of time and without a doubt are causing needless confusion in the ranks of the beginning fly fisher. I believe that the angler should study and master all aspects of fishing mayfly imitations.

WATER TEMPERATURE and its Effect on Trout Behavior

The temperature of the water can have a decided effect on the feeding activity of the trout. A clear understanding of the effects will assist the angler in knowing how the trout will react during the various seasons. The single most important factor in understanding how water temperature effects the trout and how they will feed is not just a knowledge of the water temperature on the day you are fishing but also a knowledge of what the water temperatures have been running. We know that the optimum water temperatures for trout activity levels are between 48 degrees and 68 degrees. During this optimum period the average healthy trout will digest its food within a 4 to 11 hour period. Once the water temperatures rise above 72 or drop below 48 degrees it slows down the metabolism of the trout. (Meaning more time is required for the trout to digest its food.) Over a period of several years I have studied this function of water temperature as related to metabolic rate and have formed the following conclusions.

The effect of water temperature on the metabolic rate of the trout is relative to the stream and area. Example: Yellowstone River, January 6th to February 15th, average water temperature 33 degrees; results trout activity very low. February l6th to February 25th slow warming of the water temperature from 33 to 42 degrees. By the time the temperature reached 42 degrees the trout activity had increased considerably. The temperature held at 42 degrees for 30 days. By the 15th day there was a drop in the activity levels. The levels did not increase again until water temperature increased to 46 degrees. Thus I concluded that the trout's activity levels will rise for short periods as the water temperatures rises until the optimum range is reached.

On the other end of the scale I find that the trout on the Yellowstone are not affected until the water temperature reaches 72 degrees. Then a slowdown is evident. Therefore, the angler needs to obtain information on the water temperature variations if dry fly fishing during the early or late seasons. My studies have also shown that this will vary from river to river around the state. Therefore what holds true on the Yellowstone may not be true during the same time period on the Big Horn.


I want to mention that there are some differences between fishing for hatchery trout versus wild trout. Thank God that the only hatchery trout in Montana are stocked in lakes. But in many parts of the country hatchery trout are planted in streams each year. Treating hatchery trout as you would a wild trout or vice versa is a mistake. Studies have shown that it takes the hatchery trout up to 90 days to become acclimated to a stream (those that survive).

Hatchery trout are used to being fed at a given time each day and during those periods will often rise to almost any fly, (though I prefer a well-trimmed Irresistible).

Remember these trout haven't been fighting a current or eating living food forms. When first planted they will often school up and hold in water that most wild trout would avoid. So if you do travel to someplace that stocks trout you might want to find out when they were planted. Armed with this information you can better plan what to use and where you will fish.

Comment on this article

Archive of the Eye of the guide

[ HOME ]

[ Search ] [ Contact FAOL ] [ Media Kit ]

FlyAnglersOnline.com © Notice