Astaxanthin is listed as an ingredient of many fish foods, including ones that used to be made by the Fish Fuel Co. It improves the colour of some types of fish, as well as having some health benefits.
Astaxanthin is a naturally occurring substance but some legislatures list it as a food colouring. It is a carotenoid pigment that occurs in trout, microalgae, yeast, and shrimp, among other sea creatures. It’s most commonly found in Pacific salmon and is what gives the fish its pinkish colour.
An antioxidant, astaxanthin is said to have many health benefits. It’s
been claimed to promote healthier skin, endurance, heart health, joint pain,
and might possibly even have a future in cancer treatment. Many of the claims have not been conclusively proved.