What and how do fish see? Understanding the answer to this question will make one a better angler.
Fish have a well-developed sense of sight, which allows them to find food, cover, mates, and avoid being eaten in the underwater "fish eat fish world." Their eyesight is on par with ours, as many fish species, but not all, see color and some can literally see in the dark.
A basic understanding of eyesight in fish and how a fish actually sees underwater can help anglers in a variety of ways. To catch a fish, you must catch its eye. Smell and sound may trigger the initial reaction but most game fish make their final attack strictly by eyesight. Salmon, lake trout, steelhead, large and smallmouth bass, walleye, pike and muskies are species that fit this classification.
A fish eye is like the human eye in many respects, but different in shape. A fish eye is round, rather than flattened like ours and it can't change the focus by adjusting its shape. This makes fish "myopic" nearsighted. Goldfish have one of the best distance visions among finny creatures, being able to see 15 feet. The limited distance vision is not a handicap as most light is reflected off the surface of a lake or stream. In very clear lakes 95 percent or more of the light is filtered out in the first 25 feet, while most light is gone in the top couple of feet in murky lakes or streams. Lake Superior is an example of the clear water bodies, while the Montreal River and it's tannic-acid stained water is in the latter category.
A fish's range of vision is excellent, being able to see in almost a complete circle, the only "blind spot" being toward the tail area. If any of you stream anglers have watched a trout at its feeding station, it will occasionally turn left and/or right. This action allows it to see everything around its feeding zone. While most of the range of a fish sight is monocular, they have binocular vision (as humans have) in the area directly in front of them.
Lesson: When fishing, especially in streams, approach from downstream and cast ahead or slightly to the side. This is what I do when flipping spinners or casting flies, in streams, as quietly and stealthily as possible, keeping in mind their sense of sound (vibrations) also.
Another question anglers frequently ask is "Can fish see colors?" The answer is an emphatic "YES!" If the answer was no, anglers would not need a tackle box full of different colored lures and it would put most lure manufactures out of business.
However, there is more to the story Scientists have shown fish can distinguish 24 different hues in the color spectrum and some can exceed human range in the violets. Anglers also need to understand that when sunlight penetrates water, the reds and yellows are filtered out first and the blues and greens last. In Lake Superior, a red lure trolled much below 25 feet will appear black; therefore a green, blue, or violet lure might be a better choice.
Some fish can also literally see in the dark, with our Portage Lake walleye being in this category. They have a substance called tapetum lucidum, which is a layer of tissue immediately behind the retina. This gathers any and all available light, which allows the walleye to literally see in the dark and is why many knowledgeable anglers fish them after sunset. Their eye glows in the dark and is why they are so aptly named. Other common names they have are: Eyes, Marbleye and glass-eye.
In summary, anglers should remember vision plays a very important role in a fish's feeding behavior, but not totally. If a lure looks good, smells good, vibrates and tastes good, it will catch more fish!