The Beryciformes are a poorly-understood order of carnivorous ray-finned fishes consisting of 7 families, 30 genera, and 161 species. They feed on small fish and invertebrates. Beyond this, little is known about the biology of most member species because of their nocturnal habits and deepwater habitats. All beryciform species are marine and most live in tropical to temperate, deepwater environments. Most live on the continental shelf and continental slope, with some species being found as deep as 2,000 m (6,600 ft). Some species move closer to the surface at night, while others live entirely in shallow water and are nocturnal, hiding in rock crevices and caves during the day. Several species are mesopelagic and bathypelagic. Beryciformes' bodies are deep and mildly compressed, typically with large eyes that help them see in darker waters. Colors range from red to yellow and brown to black, and sizes range from 8–61 cm (3.1–24.0 in). Member genera include the alfonsinos, squirrelfishes, flashlight fishes, fangtooth fishes, spinyfins, pineconefishes, redfishes, roughies, and slimeheads. A number of member species are caught commercially, including the alfonsino, the splendid alfonsino, and the orange roughy, the latter being much more economically important. Some species have bioluminescent bacteria contained in pockets of skin or in light organs near the eyes, including the anomalopids and monocentrids.
Parrotfish are a group of fish species traditionally regarded as a family (Scaridae), but now often treated as a subfamily (Scarinae) or tribe (Scarini) of the wrasses (Labridae). With roughly 95 species, this group's largest species richness is in the Indo-Pacific. They are found in coral reefs, rocky coasts, and seagrass beds, and can play a significant role in bioerosion.
The snailfishes or sea snails are a family of marine ray-finned fishes. These fishes make up the Liparidae, which is classified within the order Scorpaeniformes.
The Cetomimiformes or whalefishes are an order of small, deep-sea ray-finned fish. Some authorities include the whalefishes as part of the order Stephanoberyciformes, within the superfamily Cetomimoidea. Their sister order, the Beryciformes, includes the flashlight fish and squirrelfish.
Ophichthidae is a family of fish in the order Anguilliformes, commonly known as the snake eels. The term "Ophichthidae" comes from Greek ophis ("serpent") and ichthys ("fish"). Snake eels are also burrowing eels. They are named for their physical appearance, as they have long, cylindrical, snake-like bodies. This family is found worldwide in tropical to warm temperate waters. They inhabit a wide range of habitats, from coastal shallows and even rivers, to depths below 800 m (2,600 ft). Most species are bottom dwellers, hiding in mud or sand to capture their prey of crustaceans and small fish, but some are pelagic.
The rainbow runner, also known as the rainbow yellowtail, Spanish jack and Hawaiian salmon, is a common species of pelagic marine fish of the jack family, Carangidae. The species is widespread throughout the tropical and subtropical waters of the world, inhabiting both coastal and offshore areas. The species is the only member of the genus Elagatis, which was created 15 years after its initial description, and is closely related to the amberjacks. The rainbow runner is easily distinguished by its body shape, and the brilliant colouration which gives the fish its name. It is a fast-swimming predator, taking small fish, cephalopods, and a wide variety of planktonic crustaceans. The species reaches sexual maturity around 60 cm (24 in), and spawning takes place at different times, with some populations spawning year round, while others only spawn at certain times of the year. The species is a well known game fish, taken by a variety of fishing methods, and is a well-regarded table fish. Large numbers of the species are taken as bycatch in tuna- and shark-fishing operations and marketed.
Fish are very diverse animals and can be categorised in many ways. Although most fish species have probably been discovered and described, about 250 new ones are still discovered every year. According to FishBase about 34,800 species of fish had been described as of February 2022, which is more than the combined total of all other vertebrate species: mammals, amphibians, reptiles and birds.
Photoblepharon palpebratum, the eyelight fish or one-fin flashlightfish, is a species of saltwater anomalopid fish of the order Beryciformes. It is native to the western and central Pacific Ocean where it is found along seaward reefs close to the ocean floor, usually near rocks and corals it can use as cover. At only 12.0 cm (4.7 in) in length, it is a small fish, and more stout than other members of its family. Its body is mostly black, with a line of reflective scales running the length of its body and a distinguishing white spot at the upper corner of its preopercle. Its most notable features are its subocular bioluminescent organs which it likely uses to attract and find prey, confuse predators, and communicate with other fish. These organs are blinked on and off by the fish using a dark lid that slides up to cover them.
The splitfin flashlightfish or two-fin flashlightfish is a species of fish in the family Anomalopidae. It is found in warm waters in the central and western Pacific Ocean near shallow reefs 200–400 m (660–1,300 ft) in depth. It can grow to a length of 35 cm (14 in) TL. It is the only known member of the genus Anomalops.
Photoblepharon is a genus of poorly understood flashlight fishes found around reefs in the western Pacific Ocean (P. palpebratum) and in the western Indian Ocean (P. steinitzi). Both of its species are nocturnal predators, hiding in caves and crevices during the day and emerging at night to feed. They are small fish, 11.0–12.0 cm (4.3–4.7 in) maximum length, and of little commercial value, although fishermen have been known to use their light organs as bait. Like other anomalopids, they are notable for the white organs containing bioluminescent bacteria underneath their eyes, which, by emitting a blue-green light, allow the fish to search for food, evade predators, and communicate with other fish. Both species have black lids that slide up to cover the organ when the fish does not want to emit light. Although similar in appearance, they can be easily distinguished by the preopercle, which has a medium-sized white spot in P. palpebratum, whereas in P. steinitzi, it is much smaller and much darker, or not present at all. Neither species has been evaluated by the International Union for Conservation of Nature (IUCN) and their nocturnal natures make collection difficult and sightings uncommon.
Phthanophaneron harveyi, the Gulf flashlightfish, is a species of saltwater fish of the family Anomalopidae. It is endemic to the Gulf of California. This cryptic fish is the only known member of the genus Phthanophaneron. It was first reported in the Pacific Ocean in 1976 and is extremely rare.
Acropoma is a genus of fish in the family Acropomatidae, the temperate ocean-basses or lanternbellies. They are native to the Indian Ocean and western Pacific Ocean. They are characterized by a ventral luminous organ that has a luminous gland, a lens, and a reflector. The shape of the luminous organ helps distinguish the species in the genus.
Parmops coruscans is a species of flashlight fish native to the Pacific Ocean off the coast of Tahiti and from Fiji to French Polynesia. It is one of two species of Parmops along with P. echinatus, which was discovered off the coast of Fiji. Like other anomalopids, it is notable for the light organs underneath its eyes, which contain bioluminescent bacteria. To cover the organs, it rotates them down while sliding a black lid upward over each eye. The lack of development in its shutter mechanism helps place it between Anomalops and Phthanophaneron on the evolutionary tree.
Parmops echinatus is a species of flashlight fish found in the western Pacific Ocean. It was first described in 2001 from two specimens caught off the coast of Fiji at depths of 440 m (1,440 ft) and 550 m (1,800 ft).
The flashlight fish is a species of anomalopid fish of the order Beryciformes. It is native to the western Indian Ocean and the Red Sea where it is found near coral reefs. It is a nocturnal predator, hiding in crevices and caves by day and emerging to feed at night. At 11.0 cm (4.3 in) in length, it is small and relatively stout. Its body is mostly solid black, with the exception of white discoloration around its pectoral fins and a lateral line of reflective scales. It is most notable for the bioluminescent organs located underneath its eyes, which it uses to find prey, evade predators, and communicate with other members of its species. Like other Beryciformes, its reproduction is oviparous. It has no commercial value, and this combined with its timid, nocturnal nature makes population sizes and trends unknown. It is listed as Least Concern by the International Union for Conservation of Nature (IUCN) due to a wide distribution and lack of known threats.
Protoblepharon mccoskeri, the Taiwanese flashlight fish, is a flashlight fish species found in the Northwest Pacific off of Taiwan's east coast. It can be found as deep as 300m. It was first described in 2012 from a single specimen caught near Taiwan.
Protoblepharon rosenblatti, the Cook Islands flashlightfish, is a species of flashlight fish found in the waters surrounding the Cook Islands. It can reach lengths of up to 22.0 cm (9 in) and can be found as deep as 274 m (900 ft).
Notothenia coriiceps, also known as the black rockcod, Antarctic yellowbelly rockcod, or Antarctic bullhead notothen, is a species of marine ray-finned fish, belonging to the family Nototheniidae, the notothens or cod icefishes. It is widely spread around the Antarctic continent. Like other Antarctic notothenioid fishes, N. coriiceps evolved in the stable, ice-cold environment of the Southern Ocean. It is not currently targeted by commercial fisheries.
A micronekton is a group of organisms of 2 to 20 cm in size which are able to swim independently of ocean currents. The word 'nekton' is derived from the Greek νήκτον, translit. nekton, meaning "to swim", and was coined by Ernst Haeckel in 1890.
