I must have lucked out! My CAE seem to be very sociable with their other tank mates. The tetras go all around them; even the Oto and the Cory can share the same algae/shrimp tabs while the CAE munches. But when the two CAE are together-- they chase each other. Each one, though, has his/her own cave, so they have their own territory to retreat to. I will keep watching them and make sure they do not get too aggressive.