With CA/SA fish its more about territorial aggression...in most cases overstocking like in African setups just results in serial murder...but depending on the lottery u could end up with a community in a bigger tank (risky). Most American cichlids want to be king of the hill regardless of tank size. If you want a wet pet a solo Oscar is great and imo better than a tank of Tropheus or predator haps; however, this is the individual fish lovers perception. Different strokes. I would go Amphilophus as a wet pet myself ?