Yeah, pretty much what 'Haplochromine Guy' says.
The reason I recommend keeping a single male Convict, is that for an individual of this species I personally think they offer a bit 'more' fish to look at than female Convicts do.
- A bit larger size.
- That nuchal hump!
- Long, flowing dorsal and anal fins.
The male convict is a pretty fish! And the reason I suggested the Firemouth, is that in four foot long tanks with other/dither fish swimming around - an individual Convict and Firemouth will tend to get along pretty good together. The Danios will definitely help in providing distractions for both of them to keep an eye on in there. Plus, neither cichlid will behave or look much like the other one. And, both of these cichlids look pretty awesome when adult sizes are attained.
A nice community tank! 8)