Rhodomonas is a genus of cryptomonads.[1][2] It is characterized by its red colour, the square-shaped plates of its inner periplast, its short furrow ending in a gullet, and a distinctly shaped chloroplast closely associated with its nucleomorph.[3] Historically, Rhodomonas was characterized by its red chloroplast alone,[4] but this no longer occurs as its taxonomy has become increasingly based on molecular and cellular data.[5][6] Currently, there is some debate about the taxonomic validity of Rhodomonas as a genus and further research is needed to verify its taxonomic status.[4][7]Rhodomonas is typically found in marine environments, although freshwater reports exist.[4] It is commonly used as a live feed for various aquaculture species.[8]