Genus Peridinium is a type of freshwater algae that comprises numerous species, which exhibit diverse characteristics. Some of the synonyms for this genus include Dinophysis, which is also a type of algae but commonly found in saltwater environments. Another synonym is Glenodinium, which is characterized by its body shape and size, and can be found in freshwater bodies. Ceratium is another synonym that comprises numerous species, some of which are similar to Peridinium, but they are known for their unique horns protruding from their cell body. Additionally, Noctiluca is a synonym that refers to a species of dinoflagellate algae, notable for its bioluminescence, which often appears like a bright blue glow on the surface of water bodies at night.