Convicts would work, blood parrots, Oscars (although tank is not really big enough), Silver Dollars, Green Terrors, Jack Dempseys, Texas Cichlid.
Just a few off the top of my head. If you want a blue coloured fish than the JD is probably the best one. Although it may not work out, JD's can be very aggressive. Might work though if you add a small JD though if the firemouth is of a good size. But might have to have a backup plan if the JD is a nasty, some are fine others aren't.