Lanternfish are well known for their diel vertical migrations: during daylight hours, most species remain within the gloomy bathypelagic zone, between 300 and 1,500 m (980 and 4,920 ft) deep, but towards sundown, the fish begin to rise into the epipelagic zone, between 10 and 100 m (33 and 328 ft) deep. Some lanternfish species (family Myctophidae) Lanternfish use ventrolateral (belly) photophores as counterillumination to camouflage their silhouette when viewed from below. Shallow-living species are an iridescent blue to green or silver, while deeper-living species are dark brown to black. Lanternfish are generally small fish, ranging from about 2 to 30 cm (0.79 to 11.81 in) in length, with most being under 15 cm (5.9 in). This is true for the luminous caudal patches, with the males' being typically above the tail and the females' being below the tail. In some species, the pattern varies between males and females. The photophores emit a weak blue, green, or yellow light, and are known to be arranged in species-specific patterns. Some may also possess specialised photophores on the caudal peduncle, in proximity to the eyes (e.g., the 'headlights' of Diaphus species), and luminous patches at the base of the fins. In all but one species, Taaningichthys paurolychnus, a number of photophores (light-producing organs) are present these are paired and concentrated in ventrolateral rows on the body and head. Most lanternfish have a gas bladder, but it degenerates or fills with lipids during the maturation of a few species. In some species, such as those of the genus Lampanyctus, the pectorals are greatly elongated. The pectoral fins, usually with eight rays, may be large and well-developed to small and degenerate, or completely absent in a few species. The anal fin is supported by a cartilaginous plate at its base, and originates under, or slightly behind, the rear part of the dorsal fin. The fins are generally small, with a single high dorsal fin, a forked caudal fin, and an adipose fin. Lanternfish typically have a slender, compressed body covered in small, silvery deciduous cycloid scales ( ctenoid in four species), a large bluntly rounded head, large elliptical to round lateral eyes (dorsolateral in Protomyctophum species), and a large terminal mouth with jaws closely set with rows of small teeth. Commercial fisheries for them exist off South Africa, in the sub-Antarctic, and in the Gulf of Oman. Lanternfish are among the most widely distributed, diverse and populous vertebrates, with some estimates suggesting that they may have a total global biomass of 1.8 to 16 gigatonnes, accounting for up to 65% of all deep-sea fish biomass. Their sister family, the Neoscopelidae, are much fewer in number but superficially very similar at least one neoscopelid shares the common name 'lanternfish': the large-scaled lantern fish, Neoscopelus macrolepidotus. Lantern fishes are aptly named after their conspicuous use of bioluminescence. One of two families in the order Myctophiformes, the Myctophidae are represented by 246 species in 33 genera, and are found in oceans worldwide. Lanternfish (or myctophids, from the Greek μυκτήρ myktḗr, 'nose' and ophis, 'serpent') are small mesopelagic fish of the large family Myctophidae.

Lantern fish from finding nemo