The color discussion has always interested me. I’m one for understanding something to grasp it best and try to learn as much as I can on a topic to make sure I can use it to my advantage.
Understanding the color spectrum and how they are seen by trout is very interesting to me. Knowing what color fly to tie on in certain conditions is very important and can turn your day around on the water.
It would seem natural that those super bright flies should be seen from a mile away and that the trout should move some distance to eat them, but this cannot be further from the truth.
Understanding colors means understanding how the light refracts and gets absorbed in the water and how a sunny day for the angler doesn’t necessarily mean crisp, clear vision for the trout. Having the basic knowledge of what the light does and how it affects the color of a fly, and what the trout see can really change your view on fly selection.
- Trout have four types of cones in their retina, which allows them to see a wider range of colors than humans.
- Water absorbs light at different rates, depending on the color. This means that some colors are more visible than others at different depths.
- Trout are more likely to see dark colors in low-light conditions.
- UV light is invisible to humans, but trout can see it. UV flies can be a good choice for fishing in clear water.
- The color of a fly is not the only factor that determines whether or not a trout will eat it. The size, shape, and movement of the fly are also important.
When we talk about matching the hatch, most/all bugs or insects are dark in color and don’t have that bright dash of color that we tie some of our flies with. So why do those patterns work?
What happens to the pattern under the water in the deeper depths where the natural sunlight is zero, or there is very little light for the colors to work off, and most of the color has been absorbed?
These are the types of questions that roll around in the angler’s head on the water. It is at these depths that knowing things like reds are seen less than blues and violets, while attractor colors will hold better in clearer waters and brighter light conditions.
Matching the hatch insect-wise is important in any fishing scenario, but when it comes to colors and what the trout see better in certain conditions plays a massive role. In the below section, we will run through the basics for you to get a general idea of what to fish and when. Trying to make it a really simple color strategy to apply when on the water.
Decoding Trout Vision and Color Perception
Trout, humans, and all other animals have eyes for the same reasons- to see what is around, to find direction, and to identify food sources. For the most part, all eyes have a few similar components, but from this point onwards, human eyes remain a little behind in the complexity arena.
How Trout Eyes Work
The biology of trout eyes, like human eyes, have an Iris/pupil, lens, and retina, but that is where it stops. Human eyes dilate to restrict light from being received by the retina. In trout’s eyes, the retina adjusts how much light it can receive. Trout have peripheral vision, and the iris is notched to allow for enhanced frontal vision. This allows the trout to detect what is coming straight toward them in the water column.
Another key to the trout’s vision is the fact that the retina changes to capture varying light conditions but to understand this more, we need to understand the basics of light being captured by the retina.
To keep it as simple as possible, the retina has cells called ‘cones’ and ‘rods’ These cells process various light waves at different times. What’s interesting is that where humans have three cones, trout have FOUR. The fourth cone is able to process the UV light waves.
Cones- Work with and process brighter light waves REDS, BLUE, VIOLETS, and GREENS, while RODS process low light waves BLACKS, WHITES, and GREYS. The CONES and RODS move back and forth depending on the light that is coming in.
So as the daylight is about, the CONES are in front processing the brighter light wave, and then as the light drops and evening comes, the RODS move forward and starts to process the low light colors black and greys. The opposite occurs at sunrise the rods are gradually replaced with the CONES.
Basically, the brighter days, brighter colors can be detected, and in low-light conditions, the darker color is picked up first. The second element we need to add to the mix is the water depth. The deeper we go, the darker it gets. So, as mentioned earlier, a bright day doesn’t necessarily mean bright flies if you are fishing at depth.
While all the above is pretty basic in understanding, where it becomes complex is how the water affects the light wave and colors seen. Things like distance in the water, depth of the water, and clarity all play a role in how light is seen.
How Water Affects Fly Color
Water is a poor conductor of light. Color and sharpness are heavily affected by this. Water absorbs light at different rates depending on depth. So, what does this mean? Brighter (long wavelength colors) are absorbed faster, while darker colors (short wavelength) get absorbed slower, thus being more visible for longer and at greater depths.
An example of this is a red pattern at a depth of 12 feet would seem almost black in color as red gets absorbed fast, while a blue pattern at the same depth would seem darker blue because the blue color gets absorbed slower.
UV Flies and Color
UV light is a different story, we can’t see it, but trout have the fourth cone to process it, which makes it an important color to use and understand. The absorbed UV light reflects longer wavelengths along with normal wavelengths and thus creating a brighter, more fluorescence color.
These colors can be seen at depths and are ideal for deeper pools if the water is clearer. Stained water will absorb the UV rays quickly, so the colors become less significant.
As trout move from the shallows to the deeper water, their environment gets darker, and so does their perception of a fly’s color. The water lets less light in, making darker colors more noticeable.
Trout see objects with more clarity under the water than when on the surface. The surface visual is a mere silhouette. The argument here is, do the colors on our dry fly matter then? I think they do, especially when the fish comes right up to the fly to inspect.
How Far Do Trout See
Trout’s color vision is limited to shorter distances; greens are the least visible, and blues are the best, with the reds and oranges being brighter to trout than what we see them as. This will explain why a small hotspot red in the pattern is such a deadly addition to some patterns.
The old saying fish dark flies in dark conditions and light flies in light conditions rings true. The deeper you get; the less color vision trout have; ending up in the depths with a dark pattern will be the best method.
When you are fishing the shallow rivers and still waters, color is important, and be guided by what you are trying to imitate. MATCH THE HATCH.
Match what the fish are feeding on, then work backward with the colors.
Black and Dark-Colored Flies
We now know that the darker colors are the ones that will get seen for the longest, especially when fishing in the deeper, darker waters where the sunlight doesn’t reach. So, if you are fishing at night, dusk, or dawn when the light isn’t prevalent, then the darker choice patterns would be the best bet. If your water is murky or stained like tea, the better choice would again be your darker colors. It becomes more about the profile than the actual color in these conditions.
Favorite Dark Flies
The Woolly Bugger – has to be one of, if not the most popular fly patterns around. You don’t even have to fly fish, and you would have probably heard of the fly. I love them and have an entire fly box dedicated to them. It can be a search pattern, an attractor pattern, or fished as a baitfish/leech when you need it to be.
It is a very versatile pattern and one that catches loads of fish. I have them tied in blacks, olives, and browns with a few patterns having a hotspot tail or a bead for the day when the water is clearer and I need to fish at a depth.
Guide Pro Tip: Remember, the dark colors work at depth while the bright colors can refract light in the clearer water at depth as well, so this is a great combo. Murkier water stick to the darker shades as the brighter shades and UVs are wasted.
Dark Griffith’s Gnat – is a good pattern to have. If you tie it in a conventional way, the dark green peacock herl will work great for the surface profile and what the fish can see from underneath. Learn about other amazing midge patterns 👉 HERE
Strip Leech – is one of my favorites, in browns and blacks and a few olives. I’m not sure if it’s the color or the motion of the marabou fibers on the hang, but in leech conditions, the darker colors are great.
Usually fished on a suspension rig just off the weed bed tips or off the feeding lanes, the waters may not always be the clearest thus, the darker color works well here, and then on crystal clear days with gin clear waters, the darker shades with a touch of UV are killers. I’m a fan of tying my leech pattern with a touch of UV flash in for this reason. A balanced leech is a killer pattern for this method of fishing.
Many insect larvae are green, and as we know, green is one of the colors least seen by trout. But in a fast clear water stream, a free-roaming green caddis nymph pops out like a light bulb in the night, and then green is very relevant and important. In a case like this matching the hatch works in hand with the color, which would work well in those conditions.
3 Favorite Examples:
Green Caddis Larva – is a must-have pattern. Have them in different shades of green and a few in a fluorescent green as well for those deeper, clearer pools.
Greenie Weenie – Is a junk fly by definition but a great one. Junk flies are very underrated, and they can turn a tough day into a good one. The bright green abdomen tied with either Antron yarn of a mop style has a great motion when fished on a euro rig or suspension rig.
Green Bassie Nymph – this is a great version to fish as a point fly if there are a few caddis nymphs on the rocks. A gold bead and green wire body work great in clear water and low-light conditions.
Brown and Tan Flies
Browns and Tans are obviously the color of most of the food trout feed on. I would class and fish browns and tans the same as I would fish black flies in the same conditions.
I would possibly use a brown or tan variation if the day were bright, the water very clear, and I hadn’t had much success from the brighter colors.
3 Flies That Always Seem to Work
Brown Stonefly Nymph – great pattern to fish. A pattern to fish at a specific time of the year and session. The classic pattern, which is brown with its distinct legs and thorax, is very noticeable. It is here where I feel that matching the hatch is more important than the color, and any other color wouldn’t really work.
Elk Hair Caddis Dry Fly – this is a pattern that works best in the natural tan and browns it is tied in. Again, one can argue that it’s the deadly profile the fly has on the water that gives it the edge, but the darker colors do play a role, especially in clearer waters.
Parachute Adams – is a main stay in most fly boxes, it just does so many things so well. The color matches many popular mayfly duns and the cream to brown body provides a silhouette that attracts trout. Cast is the bubble lines and hold on.
Yellow and Gold Flies
Yellow and golds are colors that pop and stand out. Yellow is more so than gold. The yellows in muddler collars and in the salmon fly work as attractor/trigger colors, and generally speaking, a fish may act instinctively towards them. Gold is a color I tend to associate with beads and ribbing. These are elements of a pattern that gives it an edge or provide a trigger for the fish. A gold bead is a staple in my fly box, and while I fish other colors, gold is a very productive color in all types of waters and depths.
Yellow Stimulator – like a yellow hopper, these patterns are perfect when you need to throw a pattern that is able to float well and gives a great surface profile from the bottom. Added is the trigger color of yellow which we know to work on those brighter days.
Gold Ribbed Hare’s Ear Nymph – The gold ribbing is the key here for me. The pattern itself is deadly, with the hare’s ear having a very buggy appearance. Added to this is the popping gold color, which is killer.
White and Silver Flies
Ironically whites and silvers are best for darker waters and conditions. When the light is fading, and the trout’s eyes move towards a more black-and-white vision, then the whites and silvers pop well.
Dusk and night fishing are when they work best. The evening sunset is a great time to throw a whole death or zonker. The sun’s light is now not on the water, and the rays are around. The shift of vision to the RODS, which detects the dark colors, is what the brown trout are relying on. White is a great color to start with when presented with these conditions.
White Zonker – the zonker is a great pattern to have, a baitfish pattern that can be tied in a few different styles, all with the characteristic zonker strip over the top. White is a tail color with various body colors to mix it up.
White Death – A very underrated pattern in my mind. These little patterns are great to fish in the fading light on a washing line rig.
Red and Orange Flies
Reds and oranges fade fast when it comes to light waves being absorbed in the water column. That said, they are still great colors to have in your patterns. Red is often seen by rainbow trout to be brighter than what we humans see, and this would explain the attraction to red on some days. The clear waters call for some red, and this would be my first choice when on still water fishing at a medium depth where some light would still play a role.
2 Flies That I Love
RAB – AKA ‘Red-Arsed Bastard’ is a South African-born dry fly pattern. Getting its name from the little red tag on the hook bend, this wild, scraggly-looking pattern pulls fish from meters away. It is a staple in most dry fly angler’s boxes and is the first-choice pattern on the Easter Cape rivers of Southern Africa.
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Beyond the Hatch: The Role of Experimentation
The beauty of fly fishing is that it is such a multifaceted activity; you can literally make it as complex as you choose. One of the first things you tend to learn as a newbie is to match the hatch. This is something that is vital to your progression in the sport. A basic understanding of entomology and when to fish is all one needs to start.
The deeper you dive into this, the greater you have of becoming a more consistently good angler. But what isn’t said much in the fly-fishing world is that sometimes you just need to lose all the theories and tactics and just fish to have fun, for the same reason a kid fishes with a worm and a stick, its for that feeling of maybe catching something. We all need to go back to our inner child sometimes to reset and remind ourselves why we fly fish.
Play around with ideas and concepts; there is a ton of information available online that one can get quite lost in, use it, and play with it. You will be surprised at what the outcome will be.
One Last Cast
Choosing the correct color to fish is important, and what’s more important is that you do not want to be overthinking this waterside. You want to have a briefly summarized approach to all your waters and adapt as you need to.
- Dark flies in darker light and waters
- Lighter flies in clearer waters
- UV colors in darker, clearer waters are recommended.
- Trout see whites better in fading light and brighter colors on the sunrise.
- Trout see reds brighter than we do, and greens are the least noticeable in cleaner waters.
Understanding how to match the hatch and combining the knowledge of the best colors for certain conditions takes years to master and is a wonderful path to be on. On each trip, you learn something new. Make notes about what worked when and why you think so. Keep going back to those notes when you can. When you get it right and can confidently fish the right colors at the right times, then you will be in a great position to catch many fish and educate others along the way.
Guide Pro Tip: Learn how to tie flies in this series of articles with video 👉 How to Tie Flies
Fly fishing has been my passion and pursuit for the past 20 years. I am a South African based fly fisherman who loves nothing more than spending a day on the water. Fly fishing is more than catching fish, being in the outdoors with good friends and family is what it is all about.