Red algae are members of the phylum Rhodophyta, a large group of aquatic algae with approximately 6000 species. The red algae are characterized by reddish phycobilin pigments—phycoerythrin and phycocyanin—that mask the color of the chlorophylls. Most species grow near tropical and subtropical shores below the low-tide mark. A few are found in fresh water. Red algae is also used to make Nori.