About Nomeus gronovii (Gmelin, 1789)
Nomeus gronovii (Gmelin, 1789) is the only known member of its genus. This fish has an elongated body with large eyes and distinct dorsal fins. Its body is covered in striped blackish-blue markings, and it has an extremely forked caudal fin. It can grow to a maximum length of 39 cm (15 in), lives up to five years, and forms large groups instead of living alone. This species is found across the Atlantic, Pacific, and Indian Oceans. It typically inhabits warm, deep pelagic open ocean zones between 200 and 1,000 meters (660 and 3,280 feet). It is more common in the Pacific and Indian Oceans, and less common in the eastern Atlantic. It is a carnivorous planktivore, and is well known for its ability to live among the deadly tentacles of the Portuguese man o' war siphonophore; it feeds on the man o' war's tentacles and gonads. It holds minor importance for commercial fisheries. For reproduction, the female releases eggs that are then fertilized externally. Both the fertilized eggs and the resulting larvae are specialized to survive in open water. A single pair can produce between 100 and 1,000 offspring total, and fertilized eggs hatch within 4 to 5 days.
