if you want just a pair that grow big Dovii , Umbriferum or Festae
if you want just males look to one of these and then Veija like Melanurum , Synspilum, Maculcauda - Black Belt, Zonatum or Coatzacoalcos,
or Maskaheros Argentea, Geo Brasiliensis, Red Devil to make up numbers and you could add Paratilapia polleni, silver dollars, tinfoil barbs, Datnoids also
Crowding seems to reduce aggression when no females present but some fish can just take a dislike to someone else and start trouble
Dovii you should be able to find sub adults maybe a young pair or fry
Umbriferum I don't think it will be easy to find any sub adults but there has been fry become available
lately at about the 5-7 cm size
.Festae you should be able to find sub adults maybe a young pair or fry
you might find the Sept meeting of NSWCS interesting as we will have Mo Devlin over from the USA
he will be talking on photography and Large Americans and that includes collecting