''Pterophyllum altum'', also referred to as the altum angelfish, deep angelfish, or Orinoco angelfish, occurs strictly in the

Orinoco River 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 ...

Basin and the Upper Rio Negro watershed in Southern

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

, Southeastern Colombia and extreme Northern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Description

The species is the largest member in its genus and specimens may have a height (from tip of dorsal to tip of anal fin) of as much as . Its natural base color is silver but with three brownish/red vertical stripes and red striations into the fins. The species may show red spotting and a blueish green dorsal overcast when mature and when aroused exhibits a black operculum spot. Characteristic of this species is an acute incision or notch above the nares (supraorbital indention). All true Orinoco altum specimens show this trait. The true wildcaught Orinoco altum is very difficult to breed in captivity. Most altum angelfish are more frequently found in the well oxygenated, extremely soft waters of Upper and Middle Orinoco

tributaries A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainag ...

shed from the

Guiana Shield The Guiana Shield (french: Plateau des Guyanes, Bouclier guyanais; nl, Hoogland van Guyana, Guianaschild; pt, Planalto das Guianas, Escudo das Guianas; es, Escudo guayanés) is one of the three cratons of the South American Plate. It is a ...

Highlands, preferring a pH range between 4.5 and 5.8. These are very transparent blackwaters with almost nil conductivity. Temperature range in these waters is between . They are also found in the

Atabapo River Atabapo River is a river of Venezuela and Colombia. It forms the international boundary between the two countries for much of its length. It is part of the Orinoco River basin. See also *List of rivers of Venezuela This is a list of rivers in Ve ...

and Inirida River floodplain, down the

Casiquiare The Casiquiare river () is a distributary of the upper Orinoco flowing southward into the Rio Negro, in Venezuela, South America. As such, it forms a unique natural canal between the Orinoco and Amazon river systems. It is the world's largest ...

and Guainía floodplain where the Rio Negro is born, before entering Brazilian territory. Unlike ''P. scalare'' which prefer to spawn on the submerged leaves of plants and trees in the flooded rainforest, ''P. altum'' prefers to spawn on submerged roots and tree branches in a moderate water current. This species is recommended for intermediate to advanced aquarists due to the detailed maintenance it requires for proper health. True Orinoco Altums are usually only available in aquarium shops from late summer until early winter due to the fact that their native river system's water level is only low enough to allow for successful fishing from July to October.Mike Tuccinardi writing in Amazonas Magazine 14.12.2015 "Where to get it: True Pterophyllum altum Angelfish?"

References

altum Fish described in 1903 Taxa named by Jacques Pellegrin {{Cichlidae-stub