Marine hatchetfishes or deep-sea hatchetfishes are small deep-sea mesopelagic ray-finned fish of the stomiiform subfamily Sternoptychinae. They should not be confused with the freshwater hatchetfishes, which are not particularly closely related Teleostei in the characiform family Gasteropelecidae.
The marine hatchetfishes or deep-sea hatchetfishes as well as the related bottlelights, pearlsides and constellationfishes are small deep-sea ray-finned fish of the stomiiform family Sternoptychidae. They are not closely related to and should not be confused with the freshwater hatchetfishes, which are teleosts in the characiform family Gasteropelecidae. The Sternoptychidae have 10 genera and about 70 species altogether.
Argyropelecus is an oceanic ray-finned fish genus in the deep sea hatchetfish family Sternoptychidae. A collective name is "silver hatchetfishes", but this can also refer to a species of the freshwater hatchetfishes which are not particularly closely related to. The large pupils of these marine hatchetfishes enable them to see dim objects in the deep sea, where light barely penetrates.
Lanternfishes are small mesopelagic fish of the large family Myctophidae. One of two families in the order Myctophiformes, the Myctophidae are represented by 246 species in 33 genera, and are found in oceans worldwide. Lanternfishes are aptly named after their conspicuous use of bioluminescence. 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.
Barreleyes, also known as spook fish, are small deep-sea argentiniform fish comprising the family Opisthoproctidae found in tropical-to-temperate waters of the Atlantic, Pacific, and Indian Oceans.
Ridgeheads, also known as bigscales, are a family of small, deep-sea stephanoberyciform fish. The family contains approximately 37 species in five genera; their distribution is worldwide, but ridgeheads are absent from the Arctic Ocean and Mediterranean Sea. Although the family is one of the most widespread and plentiful of deep-sea families, none of its members are of interest to commercial fishery.
Pelagic fish live in the pelagic zone of ocean or lake waters – being neither close to the bottom nor near the shore – in contrast with demersal fish that do live on or near the bottom, and reef fish that are associated with coral reefs.
A viperfish is any species of marine fish in the genus Chauliodus. Viperfish are characterized by long, needle-like teeth and hinged lower jaws. A typical viperfish grows to lengths of 30 to 60 cm. Viperfish stay near lower depths in the daytime and shallower depths at night, primarily in tropical and temperate waters. Viperfish are believed to attack prey after luring them within range with light-producing organs called photophores, which are located along the ventral sides of its body, and with a discrete photophore at the end of a long spine in the dorsal fin reminiscent of the illicium of the unrelated deep-sea anglerfishes. The viperfish flashes this natural light on and off, at the same time moving its dorsal spine around like a fishing rod and hanging completely still in the water.
The stoplight loosejaws are small, deep-sea dragonfishes of the genus Malacosteus, classified either within the subfamily Malacosteinae of the family Stomiidae, or in the separate family Malacosteidae. They are found worldwide, outside of the Arctic and Subantarctic, in the mesopelagic zone below a depth of 500 meters. This genus once contained three nominal species: M. niger, M. choristodactylus, and M. danae, with the validity of the latter two species being challenged by different authors at various times. In 2007, Kenaley examined over 450 stoplight loosejaw specimens and revised the genus to contain two species, M. niger and the new M. australis.
Argyropelecus hemigymnus, the half-naked hatchetfish, short silver hatchetfish or spurred hatchetfish, is a deep-sea hatchetfish of the genus Argyropelecus found mesopelagically in the Atlantic, Indian, and Pacific Oceans as well as in the Mediterranean Sea. It is a small species rarely exceeding 38 millimetres (1.5 in) standard length. It feeds on zooplankton, particularly ostracods and copepods. Sexual maturation occurs at length of about 22 mm, and adult males have more developed olfactory organs than females, i.e. the species is sexually dimorphic.
Sloane's viperfish, Chauliodus sloani, is a predatory, mesopelagic dragonfish found in deep-pelagic waters across the world. The species was first described by German scientists Marcus Elieser Bloch and Johann Gottlob Schneider in their 1801 book Systema ichthyologiae: iconibus CX illustratum, volume 1. Its size can range from 64 mm to 260 mm, and it is an iridescent silver-blue color. It has two rows of photophores, one on each side of the ventral part of its body. It is believed that C. sloani adjusts the intensity of ventral photophores during diurnal migrations to camouflage itself from predators that might see its shadow from below.
Helicocranchia pfefferi, the banded piglet squid, is a small squid of the genus Helicocranchia. Adults of this species are mesopelaegic.
Argyropelecus aculeatus, the lovely hatchetfish or Atlantic silver hatchetfish, is a species of fish in the family Sternoptychidae. It may exceed 70 millimetres (2.8 in) standard length (SL). It lives in the mesopelagic zone of all oceans and performs diel vertical migration. A. aculeatus feeds on a large range of prey items; in the Gulf of Mexico ostracods and copepods dominated the diet of small individuals and euphausiids, molluscs, and fish the diet of larger ones. The silvery coloration and bioluminescence of the lovely hatchetfish allows it to hide from predators and prey in the down-welling light of the twilight zone.
Vinciguerria lucetia is a species of marine ray-finned fish in the genus Vinciguerria known by the common name Panama lightfish. It is a small bioluminescent fish, with two rows of tiny photophores along its body. It is very abundant in the tropical Indo-Pacific where it makes large vertical migrations each day.
Vinciguerria attenuata, commonly known as the slender lightfish, is a small species of ray-finned fish in the family Phosichthyidae, found in deep water in warmer parts of the Atlantic, the Indian and Pacific Oceans.
Opisthoproctus soleatus is a species of fish in the family Opisthoproctidae. It was first described in 1888 by Léon Vaillant. The species lives in most tropical seas, but is more common in the eastern Atlantic, from western Ireland to Mauritania and from Sierra Leone to Angola, and also in the South China Sea. O. soleatus can grow to a standard length of 10.5 centimetres (4.1 in) and usually live from about 500 to 700 metres deep.
Argyropelecus sladeni, or Sladen's hatchetfish, is a species of ray-finned fish in the family Sternoptychidae, found in the tropical and subtropical Atlantic, Indian and Pacific Oceans. This small fish lives in the mesopelagic zone by day and makes a daily vertical migration to the epipelagic zone at night.
Sternoptyx diaphana, the diaphanous hatchetfish, is a species of deep sea ray-finned fish in the family Sternoptychidae. It is the type species of the genus Sternoptyx, and was first described by the French naturalist Johann Hermann in Der Naturforscher 1781.
Polyipnus clarus, commonly known as the stareye hatchetfish or slope hatchetfish, is a species of ray-finned fish in the family Sternoptychidae. It occurs in deep water in the western Atlantic Ocean from the Gulf of Maine southward to the Caribbean Sea and the Gulf of Mexico. It most commonly occurs between 300 and 400 metres but can range from 40 and 830 metres.
Neoscopelus macrolepidotus, also known as a large-scaled lantern fish, is a species of small mesopelagic or bathypelagic fish of the family Neoscopelidae, which contains six species total along three genera. The family Neoscopelidae is one of the two families of the order Myctophiformes. Neoscopelidae can be classified by the presence of an adipose fin. The presence of photophores, or light-producing organs, further classify the species into the genus Neoscopelus. N. macrolepidotus tends to be mesopelagic until the individuals become large adults, which is when they settle down to the bathypelagic zone.
