lol cichlids are great. I would stick with a certin type of cichlid. (malawi's with malawis, african with african)
Convicts are good fish, but i believe will get pretty territorial any time now. Did you add them both at the same time. You might run into problems with adding new fish as they have probably "claimed" their territory in the tank.
When you decided to add new fish make sure you feed your fish, turn off the lights, rearrange the tank and then add the fish. Keep the lights off for 24 hours (atleast). This will calm them down also with the tank rearranged they will think they are in a new home and will reclaim the tank. Not sure what other people think of this idea but whenever i added new fish I put in some feeders. This sort of took the attention off of the new guys and onto the feeders. By the time the feeders were dead the new fish have been in the tank for about 3 days. Works pretty good for me.