Cardiopharynx is a monotypic

Monotypic

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

 cichlid

Cichlid

Cichlids are fishes from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei along with the wrasses , damselfish , and surfperches . This family is both large and diverse. At least 1,300 species have been scientifically described, making it one of...

 genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

. The single species, Cardiopharynx schoutedeni, is a semi-pelagic, schooling fish endemic to Lake Tanganyika

Lake Tanganyika

Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest freshwater lake...

 in east Africa

East Africa

East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...

. This fish is purely freshwater, and prefers temperatures of 23 – 28°C. It can be deemed a tropical fish

Tropical fish

Tropical fish include fish found in tropical environments around the world, including both freshwater and salt water species.Tropical fish are popular as aquarium fish, due to their often bright coloration...

. It has a high survival rate, and its populations can double in under 15 months time. Sizes of schools can reach several hundred fish. This fish is completely harmless to human life.
Its name is derived from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

words 'kardios' and 'pharynx' which mean 'heart' and 'throat'.