There are a few hundred species of cichlids in Lake Malawi, but here are some real basic generalities:
Lake Malawi has a high pH and hard water. pH in the tank should be 7.8 or higher. (Although the fish can acclimate to a bit lower pH levels, it may shorten their life cycles.)
Mbuna - Primarily algae grazers. There are a number of Genus in this group. Psuedotropheus, Labeotropheus, Petrotilapia, Labidochromis, Tropheops, Melanochromis, Cynotilapia, Iodotropheus and a few that I can't think of off the top of my head. These fish (in general) are best kept in groups with one male and multiple females. Because they're primarily algae grazers, they're very territorial. They have small stomachs and long digestive tracts which make them susceptible to Malawi Bloat. They should be fed spirulina and foods that are easily digestible. (NLS works well.) Some fish in this group, like the popular Labidochromis caeruleus, are insectivores, are not as aggressive as the others and can withstand a more varied diet. Typically both males and females are colorful although there may be variations in that coloration.
Peacocks - This is the Aulonocara group. The name is greek and means "Flute Face". Named for the pits or holes in the face which act as a type of sonar. They are found in deeper waters and in the wild feed on invertebrates, insects, etc, found under the sand. There are a number of different species, the most popular groups being the Chitande, Maylandi and Stuartgranti complexes. Females are silverish or brown in color, and only the dominant males get coloration. (nice coloration) Again, polygamous mouthbrooders that should have several females per male.
Haps - There are a large number of fish in this group with a wide range of needs. These are fish like the Protomelas, Placidochromis, Nimbochromis, Otopharynx, etc, etc. They vary in dietary needs. Fish like the Otopharynx lithobates feed of droppings of other fish. Nimbochromis and Dimidochromis speces are piscivores. Typically females lake coloration and are silverish in color. Often times they have three black dots on their sides. Males can be quite colorful and range in size from average to very large. Again, polygamous mouthbrooders.
Utaka - These are the Copadichromis species. Typically they live out in the open water and breed in the sand. Some breed on the open substrate while others breed in pits dug along side or under rocks. Males have the color, females don't. (See the pattern here. )
That's a quick, very general synopsis.
Tim
