Why Don't We See More Chartreuse in Stillwater Trout Flies?
Hotspots are having a heyday. Orange, shrimp pink, blue, purple, pick one. Granted, I've seen pretty much every color used on trout flies, but one color that doesn't wrap much iron is fluorescent green, or chartreuse. True, there are river applications where it appears: Caddis Pupa, Mops, Green Weenies, some Walt's Worms. Still, I'd wager that very little space is allocated for this color. Now think about fishing lakes. Do you recall any chartreuse flies for trout when shopping at your average fly shop?... maybe an egg pattern. But if you're in the Western US like us, you probably haven't.
I dare you to browse through UK fly catalogs, where stillwater fishing is a big deal. Chartreuse is a staple color for lake fishing. Cat's Whickers, Blobs, Boobies, names unfamiliar to us, but famous flies that often implement a fluorescent green. Still not convinced? Then you can look to spin fisherman, another guild of anglers who implement chartreuse in trout fishing. That's right, it's not just a color for Bass.
So What Are We Missing?
Trout fishing in lakes can be a daunting task. You can't post up over a fish and work him by reading his reactions until you decipher the key. Stillwater trout are constantly moving and searching. Sometimes, you won't even know if a trout is within casting distance. So your flies should be highly appealing to draw any trout near. This is where an understanding of light's physical properties becomes important. Yes this topic has been written about before, but here is a quick dose of background information.
As Depth Increases, Colors Change
Color is the product of reflected light, where some colors travel with higher energy than others. In the visible range, red is the lowest energy and is the first to distort as you travel deeper underwater. The energy of red light scatters quickly, leaving a muted dulled red, which continues to darken with depth. As you dive past 15 feet, you next distort orange, then yellow, green. Blue and violet preserve best in deeper water. Kendall Roberg did an awesome underwater video which is linked below.
You might examine this and conclude that all colors still seem mostly intact even at fifteen feet, and it's not often that stillwater fly anglers fish much deeper. So why should I care? However, consider that the same color bleed happens horizontally as well as vertically. Imagine a sphere of visibility surrounding your fly, larger or smaller based on the fly's color, and fly's depth. Plus, the further your fly projects its color underwater, the more vivid it is at closer distances.
Attraction via Color Contrast: The Case for Chartreuse
Let's reconsider the situation of not knowing if any trout are within casting distance. Now we know that certain colors present as beacons from greater distances. But there is another element to consider. The setting is also important: deep vs. shallow water, clear vs. stained water, bright vs. dark day, each can shift the appearance of color. A good rule of thumb is for dark days use dark flies. On bright days use a bright fly. For example, black will silhouette against many backdrops and remains visible at great distances. On sunny days, light colors with silver or gold accents will sparkle off of the sun. But chartreuse might be another strong searching color. Obviously bright, it glows against the blue lake setting, or green weed beds, and transmits color well at fly fishing distances. That covers the bright days. Remember, trout tend to look upwards to feed, so some days the color of the sky will have a great influence on your fly's visibility. On darker days most light is lost through the clouds, but UV light can still penetrate and supports the use of fluorescent colors which remain vivid under UV light. That covers the darker days.
Based on the above image, surface pink and purple are also color that stands out. But don't assume fish will always just go nuts over such garish colors. Some days, imitative flies will still prevail. So applications include stripping streamers for inquisitive trout, or tag-teaming attractor flies alongside imitative patterns to draw trout closer.
Though you don't see chartreuse too frequently in western fly design, there are some newer trout flies available that suggest some have figured out how to succeed with chartreuse. Matt Winkler's Shock Collar Leech and the Pyramid Lake Popcorn Beetle might be worth picking up if you want to fully prepare for future stillwater outings.
Color Choice is Important...Unless it's Not
Much has been written about colors and water depth, several references are included that provide similar information, but I urge caution in overdoing it. Consider chironomid larvae, also referred to as blood worms. These midges are often red from hemoglobin-rich blood, as they live deep in the muddy lake bottom, where oxygen can be limited. As they begin to pupate and travel towards the surface, anglers can target fish using red chironomid flies. But in deeper settings, the red isn't visible in the same way as we'd imagine. That's not to say a red fly is inappropriate, it probably just means you could fish a red or a reddish gray fly, and both match that hatch. Even though colors don't always present in water as we expect, matching the hatch is always a good strategy. It's when we start venturing into the world of attractor patterns that we should further examine color and setting.
A Final Thought for Fly Design
Stillwater trout probably lean more heavily on their senses of smell and lateral lines more so than river trout. I'm not even going to touch the smell piece, but even though color can play a role, how a fly pushes water or wiggles seem equally important.
Color Underwater. Deep-Six. http://www.deep-six.com/page77.htm
Starling, S. 2014. View From Below. Does Lure Color Matter Underwater? https://www.fix.com/blog/view-from-below-lures-underwater/
Ross, D. 2011. Fish Eyesight: Does Color Matter? Midcurrent. https://midcurrent.com/science/fish-eyesight-does-color-matter/
Roberg, K. 2016. Underwater Color Loss With GoPro 0 to 155 Feet Depth - Fishing Lure Deep Test. https://www.youtube.com/watch?v=AAJjdA6b4Ts