noun. A red carotenoid pigment, C₄₀H₅₂O₂, produced by certain microorganisms and found in some mushrooms, crustaceans, and fish. It is used in animal feed to impart color and as a dietary supplement for its antioxidant properties.

noun. A xanthophyll pigment found in many plants and animals.

"Krill oil contains vitamin E, vitamin A, vitamin D and canthaxanthin, which is, like astaxanthin, a potent anti-oxidant."

E161g  food colouring