Species: Nomeus gronovii, Man-of-war Fish

Nomeus gronovii (Gmelin, 1789)

Man-of-war Fish

Body elongate; eye large, with a fatty ring around it; mouth small, usually ends before eye; teeth small, conical, ~ 1 row on jaws; teeth on center and sides of roof of mouth, and on bases of gill arches, none on tongue; opercle thin, with 2 flat spines; gill rakers 8 + 15 -19; 2 scarcely separated dorsal fins, 1st with IX-XII spines, which fold into a groove, its origin behind (in small specimens directly over) pectoral origin, longest spine slightly longer than longest ray; anal fin I-II, 24-29; pelvic fins insert before or under pectoral base, fan shaped, attached to belly along entire length, folds into a groove; pectoral fins 19-24, long and wing-like, with oblique bases; branched mucous canal along flank; scales on head in a broad band, extending before eyes; lateral line complete, high along back. Juvenile with greatly enlarged pelvic fins and round pectoral fins, deeply forked tail fin; lateral line ends under end of dorsal fin base.

Juveniles: silvery blue with black bars and spots; pelvic fins blue-black with white blotches; adults: uniformly dark brown.

Size: reaches 40 cm.

Inhabits surface layers of the high seas; young are associated with drifting Man-of-War siphonophores (Physalia).

Depth: 0-1000 m.

Worldwide in warm temperate and tropical seas. North Carolina to the S Caribbean.