A flagellated protozoan is a single-celled organism that possesses one or more flagella for movement. Flagellated protozoans are commonly found in aquatic environments, such as freshwater and marine ecosystems. There are several synonyms for the term "flagellated protozoan," including flagellates, mastigophorans, and zoomastigotes. These names reflect the organism's characteristic flagellar movement and help to classify it taxonomically. Flagellates play important ecological roles as primary producers, consumers, and decomposers. Some species are also disease-causing parasites in humans and animals. Understanding the diversity and functions of flagellated protozoans is essential for studying aquatic ecosystems and their associated food webs.