It appears that the use of carotenoids as pigments
in aquaculture have broader functions, including
as: (1) an antioxidant, (2) hormone precursor; and in:
(3) immune enhancement, (4) provitamin A activity,
(5) reproduction, (6) growth, (7) maturation and
(8) photoprotection. Researchers stress the vital role
that carotenoids play in physiology and in overall
health, and suggest that carotenoids are essential nutrients
that should be included in all aquatic diets at a
minimum level of 5–10 parts per million (ppm).