Gasterosteiformes
Gasterosteiformes usually have a rather small mouth, often set at the end of a tubular snout. No supramaxillary bones. The first dorsal and anal fins are usually opposite. The pelvic fins are abdominal or subthoracic. They have one spine and up to six soft rays. 1 to 5 branchiostegal rays. The caudal fin is usually rounded. Most have an armor of dermal plates.