My BP's change color depending upon moods! If scared, they become more pale...if water parameters are wacky (because i got lazy or added a new fish) same thing..pale. If one of my BP's is pale, I check the water first, filter second (its always the water!! Lazy fish Mom!), and then check to see if somebody laid eggs. I also notice that when I feed defrosted krill/bloodworms, they get a vibrant orange/pink; the same thing happens with fresh fruit and veggies (which they adore! especially pea day!). It seems that when they are not happy with something they tend to become paler shades.