Basic colors, black, red, green, size almost seems more important than color. And then there is presentation! I saw rainbows of color in some boxes last spring. I prefer fishing leeches even when the others were fishing chronomids. Caught many more bigger fish on leeches.
reddish-browns, otherwise know as leech brown, In early April use black and as the summer comes in start changing to lighter colors in browns and greens, for chironomids. I was up at a YR lake the other day and saw the thickest black chironomid hatch I have ever seen. . .