''Cichla orinocensis'', sometimes known as the Orinoco peacock bass, is a very large species of

cichlid Cichlids are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, the Labroidei, along with the wrasses ( Labridae), in the order Perciformes, but molecular studies have contradicted this ...

. This

peacock bass Peacock bass or Brazilian tucunaré are large freshwater cichlids of the genus ''Cichla''. These are diurnal predatory fishes native to the Amazon and Orinoco basins, as well as rivers of the Guianas, in tropical South America. They are someti ...

is native to the Rio Negro and

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 ...

River basins in northern

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 mainly occurs in

blackwater river A blackwater river is a type of river with a slow-moving channel flowing through forested swamps or wetlands. As vegetation decays, tannins leach into the water, making a transparent, acidic water that is darkly stained, resembling black te ...

s. Despite the name, it is not the only peacock bass in the Orinoco, as the river also is home to '' C. intermedia'', '' C. nigromaculata'', and '' C. temensis''. Where it overlaps with the last species, ''C. orinocensis'' prefers more slow-moving and shallow waters. They are able to tolerate more turbid waters than other species of peacock bass. It reaches up to about in

standard 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 m ...

. Adults are easily recognized by the three large gold-edged dark spots on the side of their body (a fourth spot on the tail) and lack of dark markings on the operculum. A genetic study has indicated a clear

divergence In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of the ...

between the Orinoco and Rio Negro populations. If split, the Orinoco would retain the scientific name ''C. orinocensis''.

References

{{Taxonbar, from=Q3752864 orinocensis Cichlid fish of South America Fish described in 1821 Taxa named by Alexander von Humboldt