(class Osteichthyes, subclass Actinopterygii)
An order of fish that are found in both fresh and salt water. The dorsal fin is preceded by several sharp spines, as are the anal and pelvic fins. The pelvic fins are located just behind the pectorals. Gasterosteids have rather elongate bodies with a narrow tail region. The order includes the families Gasterosteidae and Aulorhynchidae.
Subjects: Zoology and Animal Sciences.