''Hydrolycus armatus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

dogtooth characin Cynodontidae, also known as dogtooth characins or vampire tetras, are a family of predatory, characiform freshwater fishes from South America. This group is not very diverse, and includes only five genera and 14 species. Most of what is known abo ...

found in freshwater of tropical

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. It is sometimes known as the payara,SeriouslyFish:
Hydrolycus armatus.
' Retrieved 13 January 2017.OPEFE:

' Retrieved 13 January 2017. a name it shares with the related '' H. scomberoides''. This predatory fish occasionally makes its way into the aquarium trade, but it requires a very large tank. In its native range it is considered a major

gamefish Game fish, sport fish or quarry refer to popular fish pursued by recreational anglers, and can be freshwater or saltwater fish. Game fish can be eaten after being caught, or released after capture. Some game fish are also targeted commerciall ...

Distribution and habitat

This species of fish is found in the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology c ...

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...

and

Essequibo Essequibo is the largest traditional region of Guyana but not an administrative region of Guyana today. It may also refer to: * Essequibo River, the largest river in Guyana * Essequibo (colony), a former Dutch colony in what is now Guyana; * Esseq ...

basins in tropical South America. They are found in several different freshwater habitats, but often in fast-flowing water. They are typically found in deeper waters during the day. The species is locally common; in a major study of a Venezuelan

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

river, of the collected fish were ''H. armatus'', and the species was particularly common in creeks and lagoons. At least some populations are migratory.

Description

''Hydrolycus armatus'' are overall silvery. In adults the base of the tail and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

is pale yellowish, and the distal part is blackish, contrasting with a narrow white edge at the very tip (unique among ''

Hydrolycus ''Hydrolycus'' is a genus of large dogtooth characins from tropical South America, where found in the Amazon basin, Amazon and Orinoco basins, as well as rivers of the Guianas. The genus includes the largest dogtooth characins, reaching up to in ...

'' species). A typically reported maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of this fish is , but records show specimens up to in Venezuela and more than in Brazil. It typically weighs up to , but can reach almost . It has frequently been confused with the generally smaller '' H. scomberoides''. ''H. armatus'' reaches maturity when at least long. Like other

s, it has very long pointed

canine teeth In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened howeve ...

. In ''H. armatus'' these can surpass in length in large individuals. These are used for spearing their prey, usually other fish.

References

{{Taxonbar, from=Q1145988 Cynodontidae Freshwater fish of Brazil Freshwater fish of Colombia Fish of Guyana Fish of Venezuela Fish of the Amazon basin Taxa named by Sir William Jardine Fish described in 1841