Last time I had a 110G high tank 8years ago. 1-15"Giant Garaumi,1JD,1Jewel,1-14"Pleco,1-10" street smart goldfish. I had other fish in it but the Garaumi beat em up. So I removed all but what I have listed. I like a variety of cichlids but not all get along in a small tank.
Now 8 years later. Tank has been set up for 16 months. I am satisfied with my variety in my 220G. All fish were bought 2" Long and I have not lost any from fights. A little nipping here and there but nothing bad.
I like the variety rather than all the same in one tank. Different temperaments and personalities....
2 Oscars ---------9" and 6"
2 JDs-------------9" and 6"
2 Blood Parots---- Both 7"
2 FireMouths------5" and 5"
2 Synodontis Cats-8" and 8 1/2"
2 Pictus cats------6" and 4 "1/2
1 Pleco-----------4 1/2"
1 Rubber Pleco --2 1/2"
1 cory cat------- 2 1/2"
6 Convicts---Range 1" to 5"