Ah, guess I haven't done enough research on the Raphael then, and that was what I feared the answer would be for the Congo, I had just fool's hope. I have a feeling I'll end up settling for something like angels.
I can't imagine a BGK chowing down on an adult male congo tetra. Not even a senegal bichir can swallow an adult male congo tetra whole and their mouths are bigger than a BGK. Roseline sharks, filament barbs, congo tetras, and clown loaches make excellent schooling fish that would add motion to a BGK tank.