February 07, 2014
Purple and Blue Flies: Bogus on Top but Deadly Below the Surface
By Kirk Deeter
Sometimes it's good to break up the winter doldrums by going out to lunch with a guide buddy. Which is exactly what I did yesterday with John Perizzolo, who guides for Breckenridge Outfitters, and also happens to make the "Hemo Holsters" that Joe Cermele featured in F&S's Sportsman's Wish List a few months ago.
As is usually the case, we got to talking about tips and techniques, stuff that works... and stuff that doesn't work. J.P. spends a lot of time on the Colorado River, and he reaffirmed for me that when the fishing days are tough, one of his go-to flies is still the Purple Prince nymph. I've taken a shine to bright blue "Psycho Princes," and those of you who follow Fly Talk and the magazine know that I've written quite a bit on the virtues of purple and blue nymphs and streamers. J.P. and I are also still keen on adding U/V 'hotspots" on flies that we know we will fish deep.
"But what about purple dry flies, do you catch many on them?" I asked J.P.
"Nah, I don't fish them much," he answered.
I admitted to having been suckered into buying a dozen purple Parachute Adams flies last summer. I don't recall having caught any fish on them, though I gave it a good try. I wondered aloud why that was.
"You ever see any bright purple mayflies?" J.P. asked with a smile.
Point well taken. Actually, there are two points to be made here.
First, when fish are keyed on a hatch of natural insects, you need to throw a fly that looks as close to natural as possible (duh). That's size, profile and color. If trout aren't keyed on a certain bug, the real value of an attractor dry fly is its profile. Throw something big and ugly, and they might just take a whack at it. But they aren't going to think, "Gee, that's purple, I think I should eat that."
It's a completely different game under the water. Different shades of the spectrum dissipate the deeper you go. After a few feet, red starts to turn gray, and when you really dredge the bottom of a run, blues and purples are still vivid. So those flies are attention getters and great underwater attractors.
I do, however, know that pinks and reds work great as accents on terrestrials, and a hot pink San Juan worm is killer in many places, even fished deep. I don't know exactly why that is. I suppose reds and pinks are really red and pink on the surface or at shallow depths, and fish eat the worm because of its profile more than anything. But that's just a guess.
As for purple and blue, I remember talking to the late, great fish scientist Dr. Robert Behnke about this several years ago. He explained that fish can see colors, and that the violet side of the spectrum grabs their attention better below the surface. Those colors attract fish, but they don't simulate many natural things that trout eat. So when trout are on the feed, your best bet is to stick with more muted colors.
So purple and blues have great value below the surfacevand little value on top. This is another example of how some flies are designed to catch fish, and others are designed to catch anglers.
That's the theory we came up with over a couple of hamburgers anyway. Go ahead and shoot us down if you beg to differ.