The colour of the feathers of flamingos is due to the presence of particular organic substances: the carotenoids. These substances are not produced by the flamingos themselves, but they are present in the algas and in the small crustaceans (Artemia salina and others) on which the flamingos feed.

In captivity, if they don't eat algas and crustaceans, they will gradually lose their characteristic colour and turn white. Moreover, the pigments are not permanent and the feathers fallen during the moulting rapidly lose their pink coloration.