Superorder Acanthopterygii is a group of ray-finned fishes that includes over 15,000 species. Some synonyms for this superorder include the spiny-rayed fishes, the perch-like fishes, and the bony fishes with spiny fins. These synonyms describe the defining characteristic of this group, which is the presence of sharp, spiny rays in their fins. Other synonyms for Superorder Acanthopterygii include the teleosts, which refers to their advanced bony skeletons, and the neopterygians, which refers to their ability to flex their fins and adapt to different aquatic environments. Regardless of the synonym used, this superorder contains a diverse array of fish species that vary in size, habitat, and behavior.