Astaxanthin is a keto-carotenoid. Astaxanthin is a blood-red pigment and naturally originates in the rainwater microalgae (Haematococcus Pluvialis) and the yeast fungus called Xanthophyllomyces dendrorhous (also known as Phaffia). The algae under goes a stressing via one or a combination of conditions ranging from the lack of nutrients, increased salinity, and excessive sunshine to create Astaxanthin.