Lake Malawi is part of the East African Rift valley system (meaning it lies in the East African rift caused by the African tectonic plate splitting in two) and is located in southern Africa. It is the ninth largest lake in the world and the third largest in Africa with a surface area around 29,600 km. It is situated between the countries of Malawi, Tanzania, and Mozambique. The lake is often called Lake Nyssa as there is still a debate between bordering countries. Lake Malawi consists of a single large basin that is approximately 506 km long and 75 km wide at the widest point. The lake's maximum depth is 700 m and it has a mean depth of around 292 m. Lake Malawi is unusual because it does not have tides or currents.

The lake is fairly warm with a deep level temperature of around 72o and with a surface temperature of 75 - 84o. The reason for the 9o F fluctuation in temperature is that Lake Malawi lies far enough south of the equator to experience definite seasonal variations in temperature. The pH ranges from 7.7 - 8.6, the gH ranges from 4-6 dH, and the kH ranges from 6-8 dH.

There are several main cichlid habitats within the lake. The first is the sandy shoreline that makes up about 70% of the coast. Some plants live in this area, but not many. Haps and peacocks use this as their habitat. The second area is the rocky shoreline that makes up the remaining 30% of the coast. Here there is no vegetation and rocks are piled on top of each other. The rocky areas tend to be where the shores have a steep drop off. Mbunas make this their habitat (hence their name which means "rock-dweller"). The third area is the river mouths and area close to shore that are highly vegetated. These areas tend to be shallow and can also be fairly muddy. Lastly, the deep water zones that go from 30 m to 250 m deep are inhabited by some of the larger predatory cichlids.