Does Fly Colour Matter?

Fishtec fly colour header

Fly colour can make a difference

Do fish respond differently to different fly colours, or is it all in the eye of the angler? Dominic Garnett applies modern logic to that age-old question: fly-colour.

“They want something with a hint of green in it today!”

How many times have you heard anglers at your local fishery make such a claim about the flies that catch on any given day? It happens too often to be pure coincidence, but how much of this is down to the anglers as opposed to the fish?

I’ve fished with a great variety of people. Many of them swear by certain colours, others are skeptics who claim that colour is not terribly important. But who is correct? And if it really does matter, which are the best colours for fishing flies? With a little science and plenty of my own trial and error, I hope I can provide some useful tips in this blog post.

How do fish see the world?

Fly Colour - Fish Shadows

When fish look up, they often see shadows and shapes rather than distinct colours.Photo credit: Dom Garnett

Don’t assume that fish share your opinions on what’s attractive or edible-looking! Perhaps the easiest trap for anglers to fall into, is to see the world through their own, all too human, eyes. But how do fish see things? This varies massively according to factors like light levels, depth and water clarity.

As humans looking down into watery worlds, it’s fair to say we get a very different view to that of our quarry. Fish, especially those like trout, which feed on insects, tend to look up for food. They probably don’t see a wide array of colours but instead see prey silhouetted against the light of the sky. Perhaps this is why black remains one of the most effective of fly colours.

Fly tying has always used colour to play on the natural curiosity and aggression of fish. By contrast, natural prey like freshwater shrimps and various nymphs tend to be dull-coloured greens and browns. Whether it’s a subtle, shiny rib or a bright red tag on a fly, there’s value in creating interest and grabbing the attention of your quarry; nature has the opposite objective!

As a good general rule, I tend to pick dull colours and subtle flies for wild fish, and go with brighter colours and larger patterns for more aggressive stocked trout. There are also times when I turn the rules on their head. Where stock fish have been peppered with bright lures, a dark fly can bring the bites back, just as a bright, gaudy lure might produce a sudden aggressive reaction from a wild fish that has refused more natural-coloured flies.

A question of depth

Fly colour guide - depth

Fly colours become dull over depth and distance

The visibility of our flies can change quickly no matter where we’re fishing, but it’s especially true for anyone who fishes in deeper or larger waters with sinking lines.

Fish can indeed see a range of colours (their world isn’t black and white). However, scientific studies show that the colours in their visual spectrum change as depths increase. Below 40 ft, all colours appear dull or greyish. Reds and oranges are the first colours to “disappear”, followed by yellows and greens, while blue and black flies and lures tend to retain their colour best at greater depths.

The “bottom line” is, while we might confidently use flies with a little or a lot of red or yellow in the upper water layers, black and blue flies might be better choices for fishing at great depths, or when the fish have to home in on our flies from distance.

Water Clarity

Fly colours - clarity

A hint of contrast is a classic ploy to make flies stand out; this fish was fooled by a drab Cruncher enhanced with a brighter thorax.Photo credit: Dom Garnett

Depth isn’t the only consideration, water clarity matters too, which is why red and orange flies can be a bit of a lifesaver in some circumstances.

A classic example of this is when otherwise clear lakes go greenish in hot weather, due to algal blooms. One of the best tips I ever got for fishing these waters came from Steve Cullen, whose thoughts on the subject really grabbed my interest as I struggled on a real peasoup of a lake. At first I wondered whether the fish would accept the bright red and orange versions of standard flies he recommended. However, my local brown trout found them very appealing indeed. You would think that the loud colours would spook wild fish, but perhaps where clarity is poor they’re less cautious.

Another common scenario is water which, often due to acidity, looks peaty or even black. These waters are common in places like Scotland or even my favourite Dartmoor lakes. The fish will still pick out a range of flies, but one thing you notice about so many of the classic loch-style patterns is the way in which they use two contrasting tones, or even three or four colours. This is not purely decorative, but helps fish pick them out in the “stained” or blackish water.

Light Levels

Fly Colours - Light levels

Waves, cloud and the position of the sun will all affect light levels.Photo credit: Dom Garnett

Light levels vary according to the time of day, the position of the sun in the sky, weather conditions and the effect of wind and waves. As light penetration changes, so does fishes’ colour perception and visibility, making flies that combine two or more colours easier to pick out than monotone patterns.

As a general rule, black and dark flies with perhaps just a touch of brighter contrast or sparkle, tend to be universally useful. At times it can seem counterintuitive, but even when it’s dark, black works; sea trout anglers fishing the silly hours of the night still catch on jet black lures. Equally, on bright sunny days when the conditions have looked all wrong, I’ve found pike flies in black to be blank savers.

Another consideration we’ve not discussed so far is reflective materials. Using flies with a bit of flash in sunny conditions can certainly work to provoke fish, particularly with predatory species, but perhaps the biggest revelation for me, has been the use of ultraviolet (UV) reflective materials in low light conditions.

Special modern tinsels and dubbings will reflect UV light even on a dull morning or at last light. I once considered these special flash materials to be a gimmick, but these days I use them with great confidence in any low-light or depth-fishing situation, whether it is a UV rib on a nymph or a dose of UV tinsel in my predator streamers. Give it a try!

For a quick, simple and visual guide to fly colours use our infographic below:
Fishtec fly colour guide

For a full choice of Caledonia Flies as shown in this guide, visit our fly fishing tackle shop online.

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