My daughter and I went to the Woodley Park Zoo in DC on Father's Day, and there was a small aquatic area that you walk down through and can look through the glass at the fish. I was delighted to see a bunch of Geophagus Tapajos and Corydora mingling among the larger fish (6 ft long Arapaima gigas, Oscars, huge turtles) and getting along in harmony! There were even a bunch of fry and fingerlings swimming among the bunch, totally unphased by the larger fish that could easily swallow 50 of them whole. Evidently these different species can get along when there are thousands of gallons of swimming space! There was a species of catfish that closely resembled a Corydora, but it was 2' long! Anyway, I thought it was pretty neat to see and wanted to share.