Seeing Red [Archive] - Fly Fishing Forum

: Seeing Red

12-16-2003, 08:23 AM
I was watching a show last night.. I don't remember the name but it was on one of the PBS channels (2, 11 and 44) up here. and it had some great underwater shots in several loctions with mini subs. One ,the Mid altlantic ridge and another in the Carabean. The tropic shot had a tuna as bait for several preditors, and the announcer cut the lights to attract these peditors to the bait... then they tuned on a red light and claimed that fish DON'T see red.... has anyone any information on light spectrum and fish... because if that's true why use red with our flies at all?

John Desjardins
12-16-2003, 08:49 AM
I believe that they can see red objects. But, that they can only see it very close up (~ 3'). I'll pull out "What Fish See" by Colin Kanagya (sp?) tonight and look at the color plates.

Doc Duprey
12-16-2003, 09:04 AM
Light at the red end of the spectrum is absorbed by water more rapidly than the other colors, so red objects appear black below a certain depth, unless you use artificial light. Red is still quite visible in the top few feet of the water column, however.

Best regards,


12-16-2003, 09:43 AM
Doc is right on. Red Wavelengths cannot perentrate more than a few feet into the water.

Dr. Dave Ross's Book "The Fisherman's Ocean" covers this topic (as well as many others) in detail, but at the same time, is undrestandable to those of us who do not have PHDs!

12-16-2003, 11:26 AM
It's an issue of red wavelengths not being present in seawater below the depth of a few meters, and this is a result of long-wavelength light reflection and refraction; this is the reason that many nocturnal and deep-water species exhibit red coloration, as the absence of red wavelengths at depth mean that the animals are harder to spot by predators and prey. Illuminate these organisms with light containing red light and presto, you see the "true" color. Many fish are thought to be able to see a pretty broad range of colors, and I believe that red is among them. It would be hard to explain why red/yellow and red/white color patterns were such producers if red was imperceptable by the fish we pursue with rod and reel.

Jim Miller
12-16-2003, 01:13 PM
It ain't no use
unless it's chartruse
(especially deeper than 30 feet!)

The other issue is contrast
A black (or color that goes to black at depth) will contrast with a sand bottom or night sky.....same is true in a turbid trout or salmon using a big black wooly bugger or stonefly nymph.(also like a montana nymph with black & chartruse)
Tight lines

12-16-2003, 06:18 PM
So... since we fish in shallow water for color purposes then we should still make every attempt to immitate the bait COLOR and shape.... except if we fish at night.

12-16-2003, 06:52 PM
Quite honestly, I think that the color of the forage should be matched as closely as possible regardless. Predatory fish have been hunting down the same prey species for millions of years; they know what to look for, what to listen for, what chemical cues to be alert for, etc. "Match the hatch".

12-18-2003, 07:40 PM
My wet suit is black and red. When I dive, the deeper I go, the less red you see.

As far as matching the hatch. I agree and disagree at the same time. During the day light hours, I try to use a fly that matches the size and color of the bait. But during low light hours, which includes dawn and dusk, I've had better success with darker patterns.

Doc Duprey
12-19-2003, 08:08 AM
The "match the hatch" school of thought places a significant (though not exclusive) emphasis on color matching (both intensity and wavelength). However, there is an underlying assumption that the fish sees things the way we do, and that is not entirely supported by anatomy.

While it is true that both fish and human retinas are similar in that the photoreceptors are either rods (low-light receptors) or cones (color receptors), the fish retina differs in that it generally has a much higher percentage of rods than does the human. Thus, the fish has a much higher sensitivity in low light situations, but is less sensitive to color than the human.

Finally, I am not aware of any study showing that the relationship between response of rod or cone and wavelenght of light is the same in the fish retina as that in the human. So what appears to us as a green dubbing may be quite different to the fish. No simple way to know.

So "matching the hatch" in terms of color is a best guess approach rather than an exact match. It should include not only color, but size, shape and behavior to really cover all the bases (as was so well discussed in books by Datus Proper and Gary Borger, among others).

Now, as to how many angels can dance on the head of a pin...

Best regards and Happy Holidays!


12-19-2003, 11:51 AM
Color certainly means a lot more to fishermen than fish.