Lampris guttatus (common names opah,cravo, moonfish, kingfish, and Jerusalem haddock) is a large, colorful, deep-bodied pelagic Lampriform fish belonging to the family Lampridae, which comprises the genus Lampris with two extant species.
Lampris guttatus are large discoid and deeply keeled fishes with an attractive form and a conspicuous coloration. They usually reach a maximum length of 2 metres (6.6 ft) and a maximum weight of 270 kilograms (600 lb).
The body is a deep steely blue grading to rosy on the belly, with white spots in irregular rows covering the flanks. Both the median and paired fins are a bright vermillion. Jaws are vermillion too. The large eyes stand out as well, ringed with golden yellow. The body is covered in minute cycloid scales and its silvery, iridescent guanine coating is easily abraded.
They have long falcate pectoral fins inserted (more or less) horizontally. The caudal fins are broadly lunate, forked, emarginate. Pelvic fins are similar but a little longer than pectoral fins, with ca. 14–17 rays.
The anterior portion of a dorsal fin (with ca. 50–55 rays) is greatly elongated, also in a falcate profile similar to the pelvic fins. The anal fin (ca. 34–41 rays) is about as high and as long as the shorter portion of the dorsal fin, and both fins have corresponding grooves into which they can be depressed. The snout is pointed and the mouth small, toothless and terminal. The lateral line forms a high arch over the pectoral fins before sweeping down to the caudal peduncle.
Biology and ecology
This species is presumed to live out their entire lives in the open ocean, at mesopelagic depths of ca. 50–500 metres, with possible forays into the bathypelagic zone. They are apparently solitary but are known to school with tuna and other scombrids. They propel themselves via a lift-based mode of swimming; that is, by flapping their pectoral fins. This, together with their forked caudal fins and depressible median fins, indicates that they maintain themselves at constantly high speeds. Squid and euphausiids (krill) make up the bulk of their diet; small fish are also taken.
They probably spawn in the spring. The planktonic larvae lack of dorsal and pelvic fin ornamentation. The slender hatchlings later undergo a marked and rapid transformation from a slender to deep-bodied form; this transformation is complete by 10.6 millimetres standard length.
Lampris guttatus has a worldwide distribution. It can be found from the Grand Banks to Argentina in the Western Atlantic; from Norway and Greenland to Senegal and south to Angola (also in the Mediterranean) in the Eastern Atlantic; from the Gulf of Alaska to southern California in the Eastern Pacific; in temperate waters of the Indian Ocean; and rare forays into the Southern Ocean.
This species lives in tropical to temperate waters of most oceans.