''Hemichromis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of fishes from the

cichlid Cichlids () are a large, diverse, and widespread family of percomorph fish in the family Cichlidae, order Cichliformes. At least 1,760 species have been scientifically described, making it one of the largest vertebrate families, with on ...

family, known in the aquarium trade as jewel cichlids. Jewel cichlids are native to

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

. Within

West Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...

, ''Hemichromis'' species are found in creeks, streams, rivers, and lakes with a variety of water qualities, including brackish-water lagoons. As traditionally defined, the genus includes two distinctly different groups: The five-spotted cichlid group (''Hemichromis'' ''

sensu stricto ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...

'') and the true jewel cichlid group (''Rubricatochromis''), which sometimes are recognized as distinct genera. The maximum size reported for the different species of ''Hemichromis'' ranges from in total length. Maximum sizes in aquaria tend to be slightly smaller than in the wild. Many ''Hemichromis'' species are brightly colored, though brighter body coloration is generally evident during breeding.

Sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

is limited, though male jewel cichlids are typically more brightly coloured and in some species have more pointed anal, ventral, and dorsal

fins A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foil (fluid mechanics), foils that produce lift (force), lift or thrust, or provide the ability to steer or stabilize motion while travelin ...

. In some species, such as ''H. cristatus'', the females can have coloring as bright as the males. Like most cichlids, jewel cichlids have highly developed brood care. ''Hemichromis'' species typically form

monogamous Monogamy ( ) is a relationship of two individuals in which they form a mutual and exclusive intimate partnership. Having only one partner at any one time, whether for life or serial monogamy, contrasts with various forms of non-monogamy (e.g. ...

breeding pair Breeding pair is a pair of animals which cooperate over time to produce offspring with some form of a bond between the individuals. For example, many birds mate for a breeding season or sometimes for life. They may share some or all of the task ...

s and the female spawns on a flat surface such as a leaf or stone. Both parents guard the eggs, and participate in fry raising.

Taxonomy

This genus consists of two distinct groups that possibly should be moved into separate genera. The first group, the so-called five-spotted cichlids (including ''H. elongatus'', ''H. faciatus'' and ''H. frempongi''), would remain in the genus ''Hemichromis'', while the rest, the true jewel cichlids, would be moved to their own genus. In 2022, the new genus ''Rubricatochromis'' was described for the true jewel cichlids. The species level

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

of ''Hemichromis'' is not fully resolved. Although some of the localized species are well-defined, this is not the case for all the more widespread species and several distinct color forms of unclear taxonomic status are known. For example, ''H. faciatus'' of the

Nile The Nile (also known as the Nile River or River Nile) is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa. It has historically been considered the List of river sy ...

basin and those in West Africa may belong to separate species, but ''H. frempongi'' of

Lake Bosumtwi Lake Bosomtwe is the only natural lake in Ghana. It is situated within an ancient impact crater that is about in diameter. It is about south-east of Kumasi, the capital of Ashanti Region, Ashanti, and is a popular recreational area. There are a ...

might be a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''H. fasciatus''. ''H. elongatus'' of the

Congo River basin The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world list of rivers by discharge, by discharge volume, following the Amazon Ri ...

and upper

Zambezi The Zambezi (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than half of t ...

may represent a species that is distinct from ''H. faciatus'' elsewhere, and "dwarf" populations in lakes Barombi Koto and Mboandong may also be distinct. In the Nile delta, two morphologically distinct populations apparently traditionally have been included in, but might be separate from, ''H. letourneuxi'' elsewhere in the Nile system. A comprehensive study of the genus also points to the existence of two

undescribed species In taxonomy, an undescribed taxon is a taxon (for example, a species) that has been discovered, but not yet formally described and named. The various Nomenclature Codes specify the requirements for a new taxon to be validly described and named. U ...

of jewel cichlids in the

Guinea region Guinea is a traditional name for the region of the coast of West Africa which lies along the Gulf of Guinea. It is a naturally moist tropical forest or savanna that stretches along the coast and borders the Sahel belt in the north. Etymology ...

. ''H. saharae'' was generally considered a synonym of ''H. letourneuxi'' until 2014 where a genetic study confirmed its distinction, although some have opted to retain the two as a single species. The taxonomic confusion in this genus has been further complicated by fish in the aquarium trade, where frequent misidentification, hybridization between species, and

selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ...

have occurred. For example, the introduced population in Florida, which is based on aquarium fish, was identified as ''H. bimaculatus'' until the 1990s, but likely are ''H. letourneuxi'' or hybrids. A similar pattern can be seen in introduced populations elsewhere that traditionally were identified as ''H. bimaculatus'', but likely are other species, especially ''H. letourneuxi''.

Species

Currently, 13 recognized species are placed in this genus:Bitja-Nyom, Arnold Roger, et al. "A systematic revision of the five-spotted Hemichromis complex (Cichliformes: Cichlidae) from West Africa and Lower Guinea, with the description of a new species from Cameroon." ''Hydrobiologia'' (2021): 1–25. * '' Hemichromis angolensis''

Steindachner Franz Steindachner (11 November 1834 in Vienna – 10 December 1919 in Vienna) was an Austrian zoologist, ichthyologist, and herpetologist. He published over 200 papers on fishes and over 50 papers on reptiles and amphibians. Steindachner descri ...

, 1865 * '' Hemichromis bimaculatus'' T. N. Gill, 1862 (jewelfish) *'' Hemichromis camerounensis'' *'' Hemichromis cerasogaster'' (

Boulenger Boulenger is a surname. Notable people with the surname include: * Benjamin Boulenger (born 1990), French footballer * Edward George Boulenger (1888–1946), British zoologist, director of aquarium at London Zoo * George Albert Boulenger (1858– ...

, 1899) * '' Hemichromis elongatus'' ( Guichenot, 1861) (banded jewel cichlid) * '' Hemichromis exsul'' ( Trewavas, 1933) (Turkana jewel cichlid) * '' Hemichromis fasciatus'' W. K. H. Peters, 1857 (banded jewelfish, five-spot cichlid) * '' Hemichromis frempongi'' Loiselle, 1979 * '' Hemichromis guttatus'' Günther, 1862 * '' Hemichromis letourneuxi'' Sauvage, 1880 * '' Hemichromis lifalili'' Loiselle, 1979 * '' Hemichromis saharae'' Sauvage, 1880 * '' Hemichromis stellifer'' Loiselle, 1979

Aquarium care

Jewel cichlids are neither suited to beginners nor the usual community tank. Several young specimens may be kept in a spacious aquarium, with stones and wood for cover until a pair forms prior to breeding. Their innate aggression makes them good candidates for keeping in a monospecies aquarium, but this depends on a number of factors similar to all tropical cichlid fish - swimming and territory space, other aquatic inhabitants, diet and feeding frequency, and tank layout. Jewel cichlids are omnivorous and eat both live foods and fish flakes.

References

{{Taxonbar, from=Q135592 Hemichromini Hemichromis Fishkeeping Taxa named by Wilhelm Peters ru:Хемихромис-красавец

Taxonomy

Species

Aquarium care

See also

References