I have a 75 gal african tank always lots of activity and very colorful. I have 5 different types of mbuna (only one male each with a few females) 3 different types of peacocks and a hap. I also have a calvus. So I have mixed the lakes well only the calvus but he looks soo different that my other fish don't bother him but I wouldn't keep American and Africans together because one should have high ph and the other should have low ph (I know it doesn't matter but if u get close to actual conditions I get better color out of the fish.