Second, I like to use flies with colors that don't match those leaves. The tans, yellows, and browns obviously blend into the mix. On this day, I used a Royal Stimulator with a peacock herl body with a band of red floss, and as a dropper nymph, I tied on a blue Psycho Prince. The trout were all over the blue nymph all day long. I don't know if they noticed it better, if the blue shade reacted well in the light, or what. I do know that the fly looked different than anything else floating in the river that day.