I know that there are three primary species of angelfishes (p. scalare, p. leopoldi and p.altum); I also know in the wild p. scalare are found near cardinals as they snack on them and they are found in tributary with little current. What I can't find is a list of fishes commonly found with angels in the wild. Which catfishes (including cory), tetras, and other cichlid. I know in the wild they are generally warm water fishes so that would exclude those fishes found in cooler areas and fast rivers but beyond that i cannot find a good search (using google) that list the species of fishes found in their native habitat (unfortunately all i find are '15 best fishes to keep with domestic angelfishes and similar stuff that doesn't interest myself). I suppose natively they are likely blackwater fish so that narrows it a tiny bit.