Pterophyllum altum, also referred to as the altum angelfish, deep angelfish, or Orinoco angelfish, occurs strictly in the Orinoco River Basin and the Upper Rio Negro watershed in Southern Venezuela, Southeastern Colombia and extreme Northern Brazil. 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 38 cm (15 in). 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, where