I'm not judging you by your post count, but true Altums are not a fish for beginning aquarists. As far as tankmates Altums are more aggressive and predatory than other members of the genus, so any community fish that you would keep with a regular P.scalare won't be a problem for the Altums. Just avoid smaller fish that could end up as food. You might be wiser to look for a tank-bred strain of P. scalare, the regular old Angel, that have nicer finnage, or possibly Peruvian "Altums" which are actually a scalare with finnage almost as impressive as the real thing. Altums are notoriously difficult to acclimate to aquarium conditions.