Which colours are best?
Some time ago I recall a conversation in our shop about colour of flies and which colours are best for trout. James (Sinnamon) has a science degree, all I have is experience – and I read a lot. I told him about a book in my collection by New Zealander, Tony Orman – ‘Trout with Nymph’. It features a chapter which, to me, is profound – Chapter 8 ‘Supernormal Releasers’
Supernormal Releasers
This chapter talks about animal behaviour and how some features of an animal attracts mates, feeding triggers or danger. Simple animals, it says, do not look at a whole object. There are usually some simple features which they recognise and trigger them. In particular it discusses stickleback fish and how the female fish recognise males by a big red patch. Replace a fish with a piece of wood and a bigger red patch and the females get even more excited than the real thing. This is a ‘supernormal releaser’.
Orman says ‘if we could include a supernormal releaser in the artificial, it would be taken even in preference to a natural’. Orman does not attempt an exact resemblance, but a caricature that may have, shape, size, colour, sink rate or some other overly prominent feature highlighted.
He experiments on a trout and when he finds a fly that the fish will take every time he sticks religiously to that pattern. He says the development of a super pattern may take several seasons. Trout with Nymph was written in 1974 and you would do well to try and find a copy.
Perhaps RED is a supernormal releaser?
Some of the below is from ‘Gink and Gasoline’ JANUARY 29, 2024 / BY LOUIS CAHILL
“Ever watch a trout refuse your dry fly and wonder what he saw that he didn’t like? A trout’s eye serves the same purpose as ours but it functions in a very different way. The subject of how trout see the world is a complicated one but the basics are well worth your time. Understanding how the fish eye works can help you imagine the watery world they see, and it may give you some insight that will help you catch them. The following are some simple principals to keep in mind.
Water is a poor conductor of light
It affects the way fish see color as well as their visual acuity. Water absorbs light at different rates depending on its wavelength or color. Long wavelength light, colors like red and orange, are absorbed quickly while short wavelengths like blue and violet are absorbed more slowly. This means that as light passes through more and more water, warm colors fade to black while cooler colors fade more slowly. Overall, as a fish moves into deeper water his environment becomes darker, at which point the biology of the fish’s eye affects his perception of color as well.
It is not necessary however for a fish to be in deep water for its vision to be affected by the absorption of light. The rules hold true for a fish in shallow water, viewing an object at a distance. A red streamer, for example, that is running at a depth of one foot, where there is plenty of red light, will appear black to a fish viewing it from fifteen feet away. As the fish closes on the fly, however, the red will become vivid. The same would not be true at a depth of fifteen feet. At that depth the fly would remain black to the fish, even at close range.
Ultraviolet light, which we do not see but trout do, is scattered in water. Colors like white and reflective materials like flash are visible to fish at long distances but may appear blurred by this effect. These flies will get a fish’s attention from a distance and become sharper as the fish draws near.
The Biology of a Trout’s Eye
The biology of a trout’s eye is similar to ours in some ways and very different in others. Their eye has an iris, a lens and a retina with both cone cells and rod cells, much like our eyes, but each functions in a different manner. The human iris or pupil dilates and constricts to regulate the amount of light reaching the retina. The trout’s iris is fixed and the retina itself adapts to changing light levels. Human eyes focus by changing the shape of the lens. A trout’s eye focuses by moving the lens closer to, or further from, the retina. The trout’s vision is very sharp in its focus but its depth of field, to use a photographic term, is limited.
The function of the trout’s eye which is of most interest to anglers is the adaptation of the retina to changing light conditions. To understand how it works we must first understand the cone and rod cells themselves. Cone cells see color and require bright light. The trout has four different types of cone cells. Humans only have three. Each type of cone cell is sensitive to a different wavelength of light. The trout’s extra cone cells see the UV spectrum and in some species dwindle with age. The trout’s eye is also more sensitive to the red spectrum than the human’s. The color it has the least ability to discern is green and the color it sees best is blue. Rod cells are very sensitive in low light and give the trout excellent night vision. These cells do not see color. To the rod cell the world is black and white.
During times of bright light the trout’s retina is dominated by the cone cells giving it very precise color vision. Still, the fish’s ability to discern color and its visual acuity are governed by the physics of its watery environment. As the light becomes lower the retina adapts. The cone cells recede and the sensitive rod cells are exposed, engaging the trout’s night vision and turning the world slowly to black and white. This is a physical change and takes time. The trout, like almost all fish, experiences a brief period of diminished vision as conditions change.
What does this mean for the angler?
The idea is simple. Under bright conditions trout see color very well and in dim conditions they do not. It becomes a bit trickier when we start to define bright and dim conditions. Obviously a sunny day is bright but not to a trout sitting at the bottom of a deep pool. At a depth of ten feet much of the light has been absorbed and all of the red spectrum is gone. A trout sitting in shallow water on a sunny day will discern color very well at close range but not when looking at a submerged object ten feet away.
Another important thing to remember is the fish’s point of view. A fish sees a submerged object with greater clarity and color than an object on the surface. The refractive index of its cornea is almost exactly that of water, meaning a fish sees much more clearly through water than air. In addition, objects on the surface are backlight from the fish’s perspective, appearing mostly as silhouette. This makes it hard for a fish to see the color of a dry fly.
Color that is not opaque, like the translucent body of a mayfly, is much easier the fish to see. This is why dry flies with loose dubbing, translucent wing material or flash underwings work so well. It is also one of the reasons that flies which sit in the film, like parachute patterns, are effective.
What trout respond to primarily in surface patterns is the impression of the fly on the surface film. The dimples on the surface caused by the weight of the fly resting on the water are a powerful trigger and their profile tells the trout that the object is likely to be food. These impressions focus the light, causing bright spots.
Flies and indicators are not the only tackle that create these impressions. It is often the bright dimples from curly tippet that give it away to fish. This is why I fish dry flies on fluorocarbon tippet. It sinks and vanishes.
The important thing is to understand how the fish sees in a variety of conditions and what the triggers are that make him eat. Armed with this information you can make smart choices both on the stream and at the vise. Don’t be afraid to try new things. Trust your gut and see what works. Just try to see it his way.”
More on Red
If you got this far I congratulate you. We have two separate sources that talk about triggers and vision – some of which is about colour and how powerful red is close up.
Think about some of the most popular flies and their colour: Red Tag, Royal Wulff, Red and Black Matuka, Woolly Worm (red tail), Red Spinner, Zulu, Royal Humpy and more.
Now think about Claret – or dull red
Trout see these dull red colours much brighter that humans do. So we now have a whole new bunch of flies that do extraordinarily well: Claret Nymphs, Claret Dabbler, Sedgehog, Mallard and Claret, Claret Bits. All of these use Claret seals fur – a product that is getting hard to obtain. Veniard do not export it any more so if you have some treasure it. At Essential Flyfisher we have good stocks of seals fur that we have gathered up over time, so we will not run out any time soon.
As I am writing this I am also dying seals fur in a variety of colours to rebuild our stock and have included a ‘Very Dark Claret’ as well as ‘Dark Claret’ a colour I associate with Veniard, once the biggest fly tying supplier in the World. Along with Black, Dark Claret is the most popular seals fur we sell.
Seals fur can be a little more difficult to dub than some of the modern synthetics, but I don’t believe there is any better dubbing. Its straggly hairy untidy look is exactly what fish love and treat it with a good floatant and you will have a superb floating fly.
Niko Tinbergen
Ethologist Niko Tinbergen won the 1973 Nobel Prize in Biology for his research on instinctive behavior in animals. Tinbergen used various dummies to elicit nurturing, mating, and fighting behaviors. He and his students constructed fake eggs which birds would sit on, artificial female butterflies which male butterflies courted, and models of male fish which other males attacked. Some of the dummies were ingeniously unrealistic to elucidate exactly what characteristics triggered the behaviours.
Territorial male stickleback fish will not attack a fish-shaped model if its belly isn’t red, but they violently pursue some very unfish-like models when the underside is red.
Perhaps the most interesting of Tinbergen’s discoveries is that dummies can be devised which surpass the power of any natural stimuli. Tinbergen coined the phrase ‘Supernormal stimuli’. If you can find a fly that has that – well, let me know!
Mike Stevens
