Dude it really depends on the fishes personality..
for example i have a jaguar cichlid with my africans.. WHY?
because CA like hard water .. second all my africans are carnivores which makes them have the same diet..
as for the aggression
the JAG got his ass kicked the first week then everyone got along..
now i would go ahead and mix no problem as long as u match aggression and diet..
BUT ur tank is WAYYYYYYYYY to small..
even my 60 long is to small.. but i am upgrading in a few months to a 180
anyways goodluck