Trout Tips: Colors change in the water

Editor's note: The following is excerpted from TU's book, "Trout Tips," available online for overnight delivery.

Do you ever wonder why a purple Prince Nymph works, even though there are no purple bugs that look exactly like that, anywhere? It's because trout do see colors, and they are more perceptive to the violet side of the spectrum.

Part of that also has to do with the fact that red turns to gray as light is absorbed the deeper one goes in the water. Red actually looks gray 10 feet under the water (that's why you need to add a red filter when photographing under water). On the surface, with dry flies, you can't go wrong by being as natural as possible—or as "standout" as possible with an attractor.

But depending on how deep you are fishing nymphs, matching colors to match exact bugs may not be a big deal, and you might want to skew more toward an attention grabber with the right profile. 

— Kirk Deeter