Characiformes is an order of ray-finned fish, comprising the characins and their allies. Grouped in 18 recognized families, more than 2000 different species are described, including the well-known piranha and tetras.
The jellynose fishes or tadpole fishes are the small order Ateleopodiformes. This group of ray-finned fish is monotypic, containing a single family Ateleopodidae. It has about a dozen species in four genera, but these enigmatic fishes are in need of taxonomic revision.
Macrouridae is a family of deep sea fish, a diverse and ecologically important group, which are part of the order of cod-like fish, the Gadiformes. The species in the Macrouridae are characterised by their large heads which normally have a single barbel on the chin, projecting snouts, and slender bodies that taper to whip-like tails, without an obvious caudal fin but what there is of the caudal fin is often confluent with the posterior dorsal and anal fins. There are normally two dorsal fins, the anterior dorsal fin is quite high, the posterior quite low but is longer and takes up a greater proportion of the fish's back. Species in the subfamily Macrouroidinae have a single dorsal fin. The long anal fin is almost as long as the posterior dorsal fin, and sometimes it is longer. The pelvic fin is inserted in the vicinity of the thorax and normally has 5-17 fin rays but these are absent in Macrouroides. The body is covered in small scales and if they have a photophore, it is usually on the midline of the abdomen just in front of the anus. The bioluminescence of these fish is produced by symbiotic bioluminescent bacteria. The structure of the skull has been used to show their placing in the Gadiformes, but they differ from the typical cods in that they possess one stout spine in the anterior dorsal fin.
Clinidae is a family of marine fish in the order Blenniiformes within the series Ovalentaria, part of the Percomorpha. Temperate blennies, the family ranges from the Atlantic, Pacific, and Indian Oceans, in both the Southern and Northern Hemispheres. The family contains about 86 species in 20 genera, the 60-cm-long giant kelpfish being the largest; most are far smaller.
Hexagrammidae, the greenlings, is a family of marine ray-finned fishes belonging to the suborder Cottoidei in the order Scorpaeniformes. These fishes are found in the North Pacific Ocean.
The Platycephalidae are a family of marine fish, most commonly referred to as flatheads. They are relatives of the popular lionfish, belonging to the order Scorpaeniformes.
Alestes stuhlmannii is a species of fish in the family Alestidae. It is endemic to the Ulanga River in Morogoro Region of Tanzania.
Max Fernand Leon Poll was a Belgian ichthyologist who specialised in the Cichlidae. In the years 1946 and 1947 he organised an expedition to Lake Tanganyika.
The piper gurnard, also known as the piper or the lyre gurnard, is a species of marine, demersal ray-finned fish from the family Triglidae, the gurnards and sea robins. It is found in the eastern Atlantic Ocean and the Mediterranean Sea. It is the only species in the monotypic genus Trigla.
The Patagonian blennie, also known as the rock cod, is a species of marine ray-finned fish, belonging to the monotypic family Eleginopidae and monotypic genus Eleginops. It is found in coastal and estuarine habitats around southernmost South America.
Hepsetus cuvieri, the African pike, Southern African pike or Kafue pike characin, is a predatory species of freshwater ray-finned fish belonging to the monotypic family Hepsetidae, the African pike characins. This fish is found in southern Africa. It was formerly classified within the single widespread African species Hepsetus odoe but this has now been split into a number of valid species.
Nannopetersius ansorgii is a species of African tetra fish. It is found in the central Africa in the Benito (Mbini), Chiloango, Kouilou, Loeme and Ogooué rivers of Gabon and Equatorial Guinea and the Bengo and Congo River basins of Angola and Democratic Republic of the Congo.
Nannopetersius lamberti is a species of African tetra fish. It is found in the African river basins of the Ntem, the Ogooué, the Nyanga and the Kouilou Rivers.
Nannopetersius mutambuei is a species of African tetra fish in the family Alestidae. It is endemic to the Inkisi River upstream of the Sanga dam in the lower Congo River basin, in the Democratic Republic of the Congo.
Alestopetersius brichardi is a species of African tetra. It is found in the Malebo Pool, the middle Congo River, the Ruki River drainage and the Lomami River in the Democratic Republic of the Congo.
Alestopetersius hilgendorfi is a species of African tetra fish found in the middle Congo River basin in the Democratic Republic of the Congo.
Phenacogrammus bleheri is a species of African tetra fish in the family Alestidae. It is known only from a small tributary of the Bari River in the Lua River system in the Ubangi River drainage, in the middle Congo River basin in the Democratic Republic of the Congo.
Phenacogrammus deheyni is a species of African tetra fish in the family Alestidae. It is found in the middle Congo River, the Ruki drainage, of the Mongala and Aruwimi rivers in the Democratic Republic of the Congo.
Phenacogrammus polli is a species of African tetra fish in the family Alestidae. It is found in the middle Congo River basin in the Ruki River drainage, the Lomami river and the Lindi-Tshopo river in the Democratic Republic of the Congo.
Citharinus macrolepis is a species of lutefish in the family Citharinidae. It is found in tropical Africa, where it is very widespread in the Congo River basin.
