Takes a longer period of time, but yeah. Lots of people first notice it by feeding yellows too much spinach as an only option. That's when I first became curious.
When I started shrimping, I fed only spinach. My yellows started turning weird colors after a while, and I pm'ed Mord. He told me to get some food for them quick. I have an idea he had never heard or seen it before, so he tried to help the best he could. I switched foods to another shrimp only food, and they got their color back after awhile. That's when I knew there was something that caused color problems and I set out to find it. heh