Most aquarium fish thrieve in stable tapwater PH 6.5 -8.5 you have ZERO issues with ph so long as you don't try to change it chemically. Dietary requiements however are different. The JD requires a high protien diet were as the Mbunas require a lower protien higher vegitation diet. Supplimenting the Mbunas w/ Supirulina flake can easily make Mbuna's thrieve with all kinds of other fish. The problems arise with Africans and New world cichlids when it comes to territory. Over-crowding helps dissapate the Africans aggressive nature towards territory - where as more space and less fish - esp. cichlids - keeps the JD's aggression towards others in check.