Ellinopyg - A combination of five characters are diagnostic for this species: caudal peduncle keel absent, ectocoracoid reduced, dorsal spines fewer than seven, pelvic girdle absent or vestigial, and large lateral scutes absent.
Southern ninespine stickleback - A combination of two characters: lack of caudal peduncle keel, presence of large lateral scutes.
Ninespine stickleback - It lives in extremely weedy ditches and rivers as its small spines do not offer much protection.