took this from fishchanel
n 1903, Pellegrin first described P. altum as a distinct species, and to date it has been found only in the waters of the Rio Orinoco in Venezuela. P. altum differs physiologically from P. scalare in a number of ways — most obiously, the higher count of soft dorsal and anal fin rays. In addition, its long dorsal and anal fins, more vertical form and strongly concaved forehead area give it an unmistakably regal appearance. P. altum has very rarely been spawned in captivity. As a result, all specimens that you chance to see in retailers' aquariums have been imported.Although wild P. altum and P. scalare sometimes share the trait of having their dorsums flecked with reddish-black dots, only the altum will have a second dark head bar slightly indicated, running down between the dark bar passing though the eye and the bar starting at the base of the first dorsal spines. The unpaired fins of the altum do not have the light markings that P. scalare exhibits on its unpaired fins. The mouth parts of P. altum are notably extended away from the front of the head, much more than P. scalare. You will also notice that altums have a curious habit of "yawning." If you have a chance to watch this happen, you will see that when fully opened, their mouths are much larger than they actually appear when closed.