Norm also fish have multiple layers of color and some cells have the entire prism which can be changed. Iridophores contain quanine crystals that reflect different wavelengths of light, which give them an apparent color though no true pigment is present. They give off iridescence.


Here are some color differences in BG - same pond - same time (all with in 30 min.)- same diet(?). Some of these fish changed colors in the few seconds from the water to the boat.






















Colorful aren't they.