I believe it is too small, the recommended size was a 4 foot tank if I remember correctly. Although by stocking heavy it reduces aggression, the small tank space does not leave much room for them to hide. I understand he may have meant as a grow out tank as such, but with the africans I would do it right first time. It is quite a lot of money to set up, so if they kill each other due to lack of space it would be a waste!
Taken from a websit I found.
The easiest way to keep mbuna’s natural aggression from resulting in death is to keep the fish crowded. Having only a small number of mbuna in a tank always result in the death of the least-dominate fish. So never have less than six fish of any one species, use a tank of at least 200 liters size, and double the usual stocking limit of your aquarium. To compensate for the crowding you have to have very heavy biological filtration, provide lots of water movement, and change a lot of water. A 50% water change twice a week is barely adequate.
