''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 approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

Basin and the Upper Rio Negro watershed in Southern

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

, Southeastern

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

and extreme Northern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

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 an ''affluent'', is a stream or river that flows into a larger stream ('' 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 into which the ...

shed from the

Guiana Shield The Guiana Shield (; ; ; ) is one of the three cratons of the South American Plate. It is a 1.7 billion-year-old Precambrian geological formation in northeast South America that forms a portion of the northern coast. The higher elevations on ...

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 and Inirida River floodplain, down the Casiquiare 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 {{Cichlasomatinae-stub