lets put it this way...
I had a pair of Boulengeri, a trio of Ocellatus, a young pair of Albino Brichardi's, and a pair of Caudos in a 72gallon bowfront...
The Boulengeri were and still are masters of the tank even with the Brichardi's trying to breed now. The occies wont go near the boulengeri and when the Boulengeri comes near their shell the occies just duck for cover.
All fish were approx the same size.