I feed shrimp pellets, aquarian flake, fd tubifex, and algae wafers to the tank, so they get whatever they want of that. Last night I dropped a little piece of market shrimp (was on my way to feed marble sleeper goby and RTC) in to see what they'd do with it. They went at it right away. They'd bite it then shake their heads to break off a little piece.
They don't seem to be bothered by much. They aren't belligerent toward other fish or anything. Just kinda hang out with each other. The males bully each other a little and display.
I may have found a source for these and for some other ctenopoma if anyone is interested. Just waiting on a new list to see what's available.