Fluoro Doesn't Just Apply To Tippets

Recently, I read SOL’s fishing report posted on Headhunters Blog on March 20th and started thinking about what factors make the hot nymphs that he listed so effective on the Missouri River below Holter Dam. The nymphs that were catching fish at this time (as well as most of the winter) include:  Pink Lightning Bug, Amex, Rainbow Czech, Pink Ray Charles, Pink Scuds, Worm, Rainbow Warrior, Sows, Zebras, Dominick’s Dam Midge, Red Flasher, Mason’s Peep Show, and Ju-ju Baetis. Why are these particular patterns working so well this March/winter? If you don’t care why they are working and only that they do, stop reading this now, get some of these patterns, and go catch some fish. If you are curious, read on.

What do these flies have in common? Most of them incorporate fluorescent pink or orange materials. When pressed, a lot of anglers will say that these flies work because they are being taken as eggs. I think that many times this might be the case. But, what kind of egg does a Pink Lightning Bug or a Mason’s Peep Show imitate? In addition to the egg hypothesis, something else is making these top winter bugs perform so well. I think the attractive quality of these flies comes from the unique characteristics of the fluorescent materials that they incorporate. Why are fluorescent materials particularly effective?

As sunlight penetrates the water column, the longer wavelength light (red, orange, and yellow) is the first to get filtered out. This means that flies that are red, orange, or yellow will appear gray at depth. Blue and purple light penetrate the water column deeper, and flies incorporating these colors retain their coloration to a greater depth (which may explain why many steelhead flies incorporate these colors, but that is a story for another time). This principle also applies in the horizontal plane, meaning that as your nymph is drifting downstream towards a waiting trout, objects that reflect longer wavelength light (red, orange, or yellow) will appear gray and muted to trout until they are relatively close to the fish. Water clarity also plays a role. As things get muddier, objects appear even more gray and muted underwater. In other words, when a pink fly is drifting underwater towards a trout, its coloring will appear at least somewhat muted unless it is in shallow, clear water and relatively near the trout viewing it. So why would putting a fluorescent orange thread head or firebead on the same pink fly turn it into a fish catching magnet?

This is where the fluorescent materials come in. Fluorescent materials have some unique optical qualities. When light of any wavelength hits fluorescent materials, these materials continue to reflect light of their own color. This means that any light hitting a fluorescent orange firebead will still be reflected as bright orange to the eyes of the fish. The color reflected by fluorescent materials is not altered by depth or distance. Additionally, fluorescent materials are able to absorb ultraviolet (UV) light and continue to reflect their original coloration.

UV light is of a smaller wavelength than even the smallest wavelength visible light, violet, which is where its name comes from. UV light penetrates the water column to a deeper depth than any visible light. This means that even in very deep and dirty water, a fly with a fluorescent orange firebead will still appear bright orange to the fish.

Firebead Ray Charles under regular light

Firebead Ray Charles under UV light.

Mason's Peep Show under regular light.

Mason's Peep Show under UV light.

Such a fly would also become visible to the fish at the greatest horizontal distance. This means that a fish facing upstream will notice a fluorescent fly coming downstream sooner than any other object, and if the fish is able to quickly notice the fly, the chances of the fly getting eaten improve dramatically. If you check out the photos accompanying this post, you’ll see what I’m talking about. They show the fly under regular light compared with how it looks under UV light. The fluorescent hot spots really stand out.

Some of you might be ready to call bull at this point and claim, “I’ve caught millions of fish with non-fluorescent flies!!!” I’m not going to argue with you. A drab nymph will still get the job done, especially in relatively clear and shallow water. I’m only suggesting that adding a fluorescent firebead or hotspot to a fly will make it easier for a fish to notice it. And isn’t that what we all want, to get our flies noticed?

Now, let’s take another look at the nymphs that SOL mentioned in his fishing report on March 20th and try to interpret their effectiveness in the context of fluorescent materials. I examined the fluorescence of these flies by shining the shop’s UV light on them and noting what parts glowed. You can check out the fluorescent qualities of your own flies by shining a UV light into your fly box.

·      Pink Lightning Bug – The tail is somewhat fluorescent.

·      Amex – The pink dubbing in the abdomen is fluorescent.

·      Rainbow Czech – The pink hotspot is fluorescent.

·      Pink Ray Charles – The non-bead versions have a fluorescent orange thread head. The bead-head versions have a fluorescent orange firebead. Check out the photos of the firebead version that accompany this post.

·      Pink Scuds – The Hot Spot Scud and the Hunchback Scud both have fluorescent hot spots.

·      Worm – Some patterns are tied with fluorescent thread. Other patterns incorporate a firebead.

·      Rainbow Warrior – The underbody and thread collar are both tied with fluorescent orange thread.

·      Sows – Many patterns incorporate fluorescent thread heads.

·      Zebras – Often not fished with fluorescent materials, but why not?

·      Dominick’s Dam Midge – The purple flash is somewhat fluorescent.

·      Red Flasher – Like the Zebra, not very fluorescent, but flashy.

·      Mason’s Peep Show – The orange thread collar is very fluorescent. Check out the photos accompanying this post.

·      Ju-ju Baetis – The Flouro-Fiber material that the wing case and legs is tied out of is fluorescent.

If you’ve already been fishing these flies, hopefully this post will help you understand why they work so well. If you haven’t been fishing these patterns, give a few of them a shot the next time you go out. Or maybe some of you have your own secret killer patterns with fluorescent materials in them? If you have a UV light on your fly tying bench, I’d recommend shining it into your fly boxes. The results are pretty interesting. If you want to read more about fluorescent hotspots, check out this article at flytyer.com.