The East African Rift System, which is part of a 5,000-km (3,100 mi) fracture zone extending from the Limpopo valley in the south to the Jordan valley in the north, came into existence in its southern part several million years ago. Geologists suggest that magma upwelling is forcing the crust apart and that major continental plates are moving apart there. The long-term result may be another Red Sea where the valley now lies.

The Great Rift Valley contains several long deep lakes. Each lake has several rivers feeding in but only one major river flowing outward. Over the centuries minerals from the inflowing streams have concentrated in the lakes so that the water is hard and alkaline.

The southernmost of these large lakes is Lake Malawi, which makes up 20% of the country of Malawi. Lake Malawi contains, as do the other lakes in the rift valley, fish not found anywhere else in the world. These Mabuna, pronounced um-Moo-na in the local African language, are highly prized by tropical fish hobbyists who call them Cichlids (sick-lids).

The male Mabuna are very aggressive and therefore not suitable for a community tank with a mixture of species. The males protect their small rocky territories from all comers, except the females that they court. They'll drive off the females too if they aren't receptive. To keep these colorful fish, you must have a tank devoted to Cichlids.

As you can see from the pictures, they are very colorful (roll the mouse over them to see more).

The Mbuna have an unusual way of caring for their young. They lay eggs, which are picked up by the females and kept in their mouth until they hatch. Therefore, most of the eggs laid hatch into fry or small fish. Once they have hatched, the mother guards over them until they grow big enough to protect themselves.

To see a particularly nice Mabuna or Cichlid collection, come to the library in Wellesley, MA where a 150 gallon tank resides.