"Pterophyllum altum", (common name: Altum Angelfish or Orinoco Angelfish) occurs strictly in the Orinoco River Basin and they have large tities the Upper Rio Negro watershed in Southern Venezuela, Southeastern Colombia and extreme Northern Brazil. Its natural color is also silver but with three brownish/red vertical stripes and red striping patterns into the fins. The species may show red spotting when mature and when aroused exhibits a black operculum spot. Characteristic of this species is an acute incision or notch above the nares. All true (pure) specimens show this trait, whereas commercial hybrids product of crosses to Pterophyllum scalare, that are occasionally performed by breeders to sell them as "Orinoco Altum", will most likely not show this trait or show it to a much lesser degree. The true wildcaught Orinoco Altum is among the most challenging among tropical fish to breed in captivity. The species is the largest of the genus and specimens exceeding 50 cm in height (from tip of dorsal to tip of anal fin) have been reported in the wild; in aquariums, specimens are known to have grown to +40 cm. Altum Angels are more frequently found in the well oxygenated, extremely soft waters of Upper and Middle Orinoco tributaries shed from the Guyana Shield Highlands, preferring a pH range between 4.5 to 5.8. These are very transparent blackwaters with almost nil conductivity. Temperature range in these waters is between 78°F (26°C) and 84°F (29°C). They are also found in the Atabapo River and Inirida River floodplain, down the Casiquiare and Guainia floodplain where the Rio Negro is born, before entering Brazilian territory. Unlike P. scalare(mentioned above) which prefer to spawn on plants, P. altum prefers to spawn on submerged roots and tree branches. This species is recommended for intermediate to advanced aquarists due to the detailed maintenance it requires for proper health.
source - wikipedia