There may be some forum members who completely disagree but my 30 gal once had a firemouth, a black convict, and various schooling fish (rosy barbs, tiger barbs, black skirt tetras, white skirt tetras, and serpae tetras) that varied through the years. It should be noted that there were schooling fish established in the tank before adding the cichlids and that both cichlids were added together when they were young and around an inch long. Also, the tank was well decorated. The firemouth claimed one side of the tank and the convict the other and aggression was limited to displays only, neither fish ever had any nips and the other fish were left alone. The two cichlids often flared their gills and shook their heads at each other in a beautiful display. This setup lasted for about 4 years until I moved the cichlids to a 55 gal where they grew larger but behaved the same as they had in the 30 gal. Black convicts with the wild coloration of blue, red, and green markings are worth looking for.
