In zoology, a scale is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopterans, scales are plates on the surface of the insect wing, and provide coloration. Scales are quite common and have evolved multiple times through convergent evolution, with varying structure and function.
Cichlids are fish from the family Cichlidae in the order Cichliformes. Traditionally Cichlids were classed in a suborder, the Labroidei, along with the wrasses (Labridae), in the order Perciformes, but molecular studies have contradicted this grouping. On the basis of fossil evidence, it first appeared in Argentina during the Early Eocene epoch, about 48.6 million years ago; however, molecular clock estimates have placed the family's origin as far back as 67 million years ago, during the late Cretaceous period. The closest living relative of cichlids is probably the convict blenny, and both families are classified in the 5th edition of Fishes of the World as the two families in the Cichliformes, part of the subseries Ovalentaria. This family is large, diverse, and widely dispersed. At least 1,650 species have been scientifically described, making it one of the largest vertebrate families. New species are discovered annually, and many species remain undescribed. The actual number of species is therefore unknown, with estimates varying between 2,000 and 3,000.
The bowfin is a ray-finned fish native to North America. Common names include mudfish, mud pike, dogfish, grindle, grinnel, swamp trout, and choupique. It is regarded as a relict, being one of only two surviving species of the Halecomorphi, a group of fish that first appeared during the Early Triassic, around 250 million years ago. The bowfin is often considered a "living fossil" because they have retained some morphological characteristics of their early ancestors. It is one of two species in the genus Amia, along with Amia ocellicauda, the eyespot bowfin. The closest living relatives of bowfins are gars, with the two groups being united in the clade Holostei.
The Asian arowana comprises several phenotypic varieties of freshwater fish distributed geographically across Southeast Asia. While most consider the different varieties to belong to a single species, work by Pouyaud et al. (2003) differentiates these varieties into multiple species. They have several other common names, including Asian bonytongue, dragonfish, and a number of names specific to the different color varieties.
The northern snakehead is a species of snakehead fish native to temperate East Asia, in China, Russia, North Korea, and South Korea. Their natural range goes from the Amur River watershed in Siberia and Manchuria down to Hainan. It is an important food fish and one of the most cultivated in its native region, with an estimated 500 short tons (450 t) produced every year in China and Korea alone. Due to this, the northern snakehead has been exported throughout the world and has managed to establish non-native populations in Central Asia and North America. In the United States, it is found in Pennsylvania, Virginia, West Virginia, Delaware, Maryland, North Carolina, Arkansas and Mississippi.
Channa is a genus of predatory fish in the family Channidae, commonly known as snakeheads, native to freshwater habitats in Asia. This genus contains about 50 scientifically described species. The genus has a wide natural distribution extending from Iraq in the west, to Indonesia and China in the east, and parts of Siberia in the Far East. A particularly high richness of species exists in Myanmar (Burma) and northeastern India, and many Channa species live nowhere else. In contrast, a few widespread species have been introduced to several regions outside their natural range, where they often become invasive. The large and medium-sized Channa species are among the most common staple food fish in several Asian countries, and they are extensively cultured. Apart from their importance as a food fish, snakeheads are consumed in some regions as a traditional medicine for wound healing and reducing postoperative pain and discomfort, and collected for the international aquarium pet trade.
Parachanna is a genus of snakeheads native to freshwater habitats in tropical Africa. Three recognized extant (living) species are in this genus, but a phylogenetic study from 2017 indicates that a fourth, currently undescribed species also exists.
The Moronidae is a family of percomorph fishes, commonly called the temperate basses, in the order Moroniformes. These fishes are found in the freshwaters of North America and the coastal waters of the North Atlantic.
The snakeheads are members of the freshwater perciform fish family Channidae, native to parts of Africa and Asia. These elongated, predatory fish are distinguished by their long dorsal fins, large mouths, and shiny teeth. They breathe air with gills, which allows them to migrate short distances over land. They have suprabranchial organs, which are primitive forms of labyrinth organs, that develop when they grow older. The two extant genera are Channa in Asia and Parachanna in Africa, consisting of more than 50 species.
Channa gachua, the dwarf snakehead, is a species of fish in the family Channidae. The name "dwarf snakehead" is also used for several other species of small snakeheads. C. gachua is native to freshwater habitats in southern Asia, where it has a wide distribution from Iran to Indonesia. This fish is considered to be a species complex, a group of several closely related taxa with one name. It is likely at least three to four different species, and further research may differentiate them. A few species such as Channa harcourtbutleri have been separated from the complex in recent decades. The easternmost population of C. gachua is often recognized as a separate species C. limbata, while the isolated Sri Lankan population often is recognized as C. kelaartii.
Channa micropeltes, giant snakehead, giant mudfish or toman harimau, is among the largest species in the family Channidae, capable of growing to 1.3 m (4.3 ft) in length and a weight of 20 kg (44 lb). It is native to the fresh waters of Southeast Asia, but has also been introduced elsewhere and is considered invasive in Taiwan. Other names include shol machh in Bengali, red snakehead, redline snakehead, and ikan toman.
Parachanna africana, the African snakehead or Niger snakehead, is a species of fish from west-central Africa. Little is published on its biology. Limited primarily to coastal sections of rivers, it is thought to be a nest-building, thrust predator like other Channidae.
The Indian threadfish, also known as the Indian threadfin, diamond trevally, mirror fish or plumed trevally, is a large species of coastal marine fish of the jack family, Carangidae. The species is widespread in the waters of the tropical Indo-West Pacific Ocean, ranging from east Africa to India, Asia, Indonesia and Australia. Adult fish tend to inhabit coastal waters over reefs down to 100 m in depth, while juveniles inhabit a variety of environments including estuaries and seagrass beds. The Indian threadfish is similar to the other two species in the genus Alectis, with a slight concavity in the profile of the head the most obvious distinguishing feature. It is a large species, growing to 165 cm and 25 kg in weight. The species is carnivorous, consuming fishes, cephalopods and crustaceans. The Indian threadfish is of minor commercial importance, and has been the subject of aquaculture in Singapore.
A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages. The term scale derives from the Old French escale, meaning a shell pod or husk.
Parachanna fayumensis, is an extinct member of the snakehead fish family (Channidae) known from fossil records only. It is the oldest member of this family known from Africa. It differs from Parachanna insignis, P. africana and P. obscura by presence of prominent raised tooth patch with well-developed tooth sockets on a ventral surface of parasphenoid posterior end. Several skull bones were found in the upper Eocene and lower Oligocene Jebel Qatrani Formation of the Fayum Depression, Egypt. The zoogeographic importance of this fossil material is that it suggests a Channid migration from India to Africa long before the Miocene.
Channa pleurophthalma, the ocellated snakehead is a species of Southeast Asian freshwater fish in the snakehead family.
Deuterodon pelecus is a species of characid fish from Brazil. It can be distinguished from other species by: its body depth ; its short and pointed snout smaller than the orbital diameter; and a reduced number of branched anal fin rays. D. pelecus also differs from members of its genus by its characteristic color pattern. It possesses a single humeral spot that is constricted to the region above the lateral line; at the same time it shows a conspicuous midlateral body stripe from opercle to the caudal fin base, an autapomorphy of this precise species. Other Deuterodon species have a humeral spot that is vertically or horizontally elongate and have the midlateral stripe becoming faint near that humeral spot. The species name is derived from the Greek pelekus, meaning "axe", referring to the pigmentation shape resulting from the adjoinment of the humeral spot with the midlateral stripe.
The Anabantiformes, is an order of bony fish (Teleostei) proposed in 2009. They are collectively known as labyrinth fish, are an order of air-breathing freshwater ray-finned fish with two suborders, five families and at least 207 species. In addition, some authorities expand the order to include the suborder Nandoidei, which includes three families - the Nandidae, Badidae and Pristolepididae - that appear to be closely related to the Anabantiformes. The order, and these three related families, are part of a monophyletic clade which is a sister clade to the Ovalentaria, the other orders in the clade being Synbranchiformes, Carangiformes, Istiophoriformes and Pleuronectiformes. This clade is sometimes referred to as the Carangaria but is left unnamed and unranked in Fishes of the World. This group of fish are found in Asia and Africa, with some species introduced in United States of America.
Aenigmachanna gollum, the Gollum snakehead, is a species of aquifer-dwelling dragon snakehead fish that is endemic to the Indian state of Kerala.
Parachanna insignis is a species of ray-finned fish from the snakehead family, Channidae from western central Africa.
