Subclass Branchiopoda, commonly known as water fleas, comprise a diverse group of aquatic crustaceans that belong to the phylum Arthropoda. These fascinating invertebrates have a complex and unique anatomical structure that is characterized by branched gills, flattened bodies, and multiple pairs of jointed legs. The scientific community recognizes several synonyms for the Subclass Branchiopoda, including Phyllopoda, Cladocera, and Diplostraca. Researchers often use these synonyms when discussing the classification, distribution, ecology, and behavior of the diverse group of water fleas. Synonyms provide a useful tool for scientists to understand the evolutionary history of these fascinating aquatic creatures, and further investigate their ecological role in the aquatic environment.