“Fish” is a descriptive term for a vast and diverse group of over 33,000 species of aquatic vertebrates, not a single species or formal taxonomic class. All fish belong to the Kingdom Animalia and the Phylum Chordata (animals with a backbone). Taxonomically, fish are divided into three main lineages: Jawless Fish , Cartilaginous Fish, and the dominant group, Bony Fish, which is further split into Ray-Finned and Lobe-Finned types.