Altolamprologus - Tanganyika. Smaller races (A. compressiceps "Dwarf, Shell" ) can be kept as small as a 10 gallon tank, the rest (A. calvus "Black", A. compressiceps , etc...) are in the 20+ tank range. In all types, the females are about 1/2 to 1/3 the size of the males. Shells are an essential decoration in tanks housing these fish, as the females often take refuge deep inside them where the males are too large to reach. These fish feed on invertebrates, although there have been many reports that they will also consume small fish, such as Cichlid fry. These fish are very aggressive towards each other, although they tend to leave other tankmates alone. They usually form pairs and spawn in the shells, although they may practice polygamy if an excess of females is present in the tank.