Cichlids
Scientific classification
Kingdom: Animalia   Phylum: Chordata   Class: Actinopterygii   Order: Perciformes   Family: Cichlidae
Genera
See text.

Cichlids (pronounced “sick-lids”) are fishes from the family Cichlidae in the order Perciformes. The family Cichlidae, a major family of perciform fish, is both large and diverse. Estimates of species range from 1300 to 1900, making it one of the three largest vertebrate families.[1][2] They span a wide range of body sizes, from so-called dwarf species as small as 2.5 cm in length (e.g. Neolamprologus multifasciatus ) to much larger species approaching a metre in length (e.g. Boulengerochromis and Cichla). As a group the cichlids exhibit a similarly wide diversity of body shapes, ranging from strongly laterally compressed species (such as Altolamprologus, Pterophyllum, and Symphysodon) through to species that are cylindrical and highly elongate (such as Teleogramma, Teleocichla, Crenicichla, and Gobiocichla).[3] On the whole though, cichlids tend to be of medium size, round in shape and slightly laterally compressed, and generally very similar to the North American sunfishes in terms of morphology, behaviour, and ecology.^[4]

Some species, particularly the tilapiines are important food fishes, while others are valued game fish (eg. Cichla species). Many species are also highly valued in the aquarium trade.[5][6] Cichlids are also the family of vertebrates with by far the highest number of endangered species, most of these being from among the haplochromine group.[7] Cichlids are particularly well known for having evolved rapidly into a large number of closely related but morphologically diverse species within in large lakes, particularly the African Rift Valley lakes of Tanganyika, , and Victoria, and Malawi. [8][9] Many cichlids that have been accidentally or deliberately released released into freshwaters outside of their natural range have become nuisance species, for example tilapia in the southern United States.^[10]

Contents 1 Characteristics of cichlids 2 Range 3 Diet 4 Reproduction 5 Endangered cichlids 6 Hybrid cichlids 7 Cichlids as aquarium fish 8 Genera 9 Images of cichlids 10 References 11 Further reading 12 External links

Characteristics of cichlids

Cichlids are members of a group of perciform fish known as the Labroidei alongside the wrasses Labridae, damselfish Pomacentridae, and surfperches Embiotocidae. This very large grouping shares a single key trait: the fusion of the lower pharyngeal bones into a single tooth-bearing structure. A complex set of muscles allows the upper and lower pharyngeal bones to be used as a second set of jaws for processing food, allowing a division of labour between the "true" jaws (mandibles) and the pharyngeal "jaws". Cichlids in particular have evolved to be very efficient feeders that are able to capture and process a very wide variety of food items and this is assumed to be one reason why they are so diverse (see section on diet below).^[11]

The particular features of cichlids that distinguish them from the other Labroidei include:^[12]

• A single nostril on each side of the forhead instead of two.
• No bony shelf below the orbit of the eye.
• The lateral line organ is divided into two sections, one on the upper half of the flank and a second along the midline of the flank from about halfway along the body to the base of the tail (except for genera Teleogramma and Gobiocichla).
• A distinctively shaped otolith.
• The small intestine leaves the stomach from its left side, not from its right side as in other Labroidei.
• Extensive brood care, with eggs and fry being guarded by one or both parents.

Range

Cichlids are mainly freshwater fish that are most diverse in Africa and South America. Substanial numbers are also found in Central America as far north as the Rio Grande in southern Texas, and Madagascar has its own distinctive fauna of cichlids phylogenetically only distantly related to those on the African mainland. Asia largely lacks endemic cichlids except in the Levant east to Iran, Sri Lanka, and southern India.. Europe, Australia, Antarctica, and most of North America do not have any native cichlids, although where environmental conditions are suitable, for example in Florida and northern Australia, feral populations of cichlids have become established as exotics. ^{[13] [14]}

Cichlids are less commonly found in brackish and salt water habitats, though many species will tolerate brackish water for extended periods; Cichlasoma urophthalmus, for example, is equally at home in freshwater marshes and mangrove swamps, and can be found living and breeding in salt water environments such as the mangrove belts around barrier islands. ^[15] However, only a few cichlids are found primarily in brackish or salt water, most notably Etroplus maculatus, Etroplus suratensis, and Sarotherodon melanotheron. ^[16]

Diet

Cichlids are astonishingly diverse in terms of diet. Many are primarily herbivores feeding on algae (e.g. Petrochromis) and plants (e.g. Etroplus suratensis) and small animals, particularly invertebrates, are only a small part of their diet. Some cichlids are detritvores and eat all types of organic materia; among these species are the tilapias of the genera Oreochromis, Sarotherodon, and Tilapia.

Other cichlids are predatory and eat little if any plant matter. These include generalists that catch a variety of small animals including other fishes and insect larvae (e.g. Pterophyllum), as well as variety of specialists. Trematocranus is a specialised snail-eater, while Pungu maclareni feeds on sponges. A number of cichlids feed on other fish, either whole or in part. Crenicichla are stealth-predators that lunge at small fish that pass by their hiding places, while Cichla are open water pursuit predators that chase down their prey. Paedophagous cichlids such as Caprichromis species eat other species' eggs or young (in some cases ramming the heads of mouthbrooding species to force them to disgorge their young). Among the more unusual predators are Plecodus straeleni feeds on scales and fins ripped from other fishes, and Nimbochromis livingstonii, which lies on its side and plays dead, hoping to lure smaller fish close enough for it to snap them up.

Scientists believe it is this wide adaptability of feeding styles that has helped cichlids to inhabit such a wide range of habitats. It is largely the pharyngeal teeth (teeth in the throat) that allows the cichlid so many 'niche' feeding behaviors, i.e. the jaws may be used to hold or pick food, while the pharyngeal teeth are used to crush what was harvested.

Reproduction

All species show some form of parental care for both eggs and larvae, often extended to free-swimming young until they are several weeks or months old. The discus fish (Symphysodon species) are noted to feed their young with a secretion on the skin from slime glands. Other South American, some Central American and Madagascan cichlds have also been observed with fry feeding on their parents, but not to the extent of the discus. Parental care falls into one of three categories: mouthbrooders, substrate brooders, and delayed mouthbrooding where the eggs are laid in the open or in a cave, and subsequently brooded in the mouth(s) of the parents.

Endangered cichlids

Because of the introduced nile perch and water hyacinth, deforestation causing siltation of water, and overfishing, many species of Lake Victoria cichlids have been wiped out or drastically reduced in the wild. Thankfully, the myriad of satellite lakes surrounding Lake Victoria have not been affected, and harbor a vast array of similar species.

Hybrid cichlids

Some cichlids have been found to hybridise with closely related species quite readily, both in the wild and under artificial conditions.^[17] This is not particularly unusual, having been observed among other groups of fishes, such as European cyprinids.^[18] What is unusual is the extent to which cichlid hybrids have been put to commercial use, in particular as fast-growing food fish and as aquarium fish.^[19][20]

Cichlids as aquarium fish

Cichlid keeping aquarists tend to divide cichlids into groups based on regions such as Central America, South America, Madagascar and India, Lake Tanganyika, Lake Malawi and Lake Victoria. It is noteworthy that most cichlids are not the most peaceful aquarium residents, though there are exceptions to this rule.

Cichlids from Lake Tanganyika were first collected by German hobbyists during the 1930's. However, it was during the 1970s and 80s that the cichlids from lakes Tanganyika and Malawi began to become popular aquarium fishes. This trend continues to the present unabated.

Perhaps the most commonly encountered species in retail aquariums is Pterophyllum scalare, known in the trade as the "angelfish". Other cichlids commonly stocked by retail aquaria include:

• Astronotus ocellatus (oscars)
  Cleithracara maronii (keyhole cichlids)
  Hemichromis sp. (Jewel cichlids)
  Labidochromis caeruleus (electric yellows)
  Mikrogeophagus ramirezi (blue rams)
  Pelvicachromis pulcher (kribensis)
  Sciaenochromis fryeri (electric blues)
  Symphysodon discus (discus)

Species of cichlid can be kept in aquariums with other fish, however, many cichlids are aggressively territorial or predatory towards smaller fish. Conversely, some cichlids, such as Apistogramma or Julidochromis spp., can be timid in the aquarium. In such cases the use of dither fish is recommended.

Genera

Source: Froese, R. and D. Pauly. Editors. 2006.FishBase. World Wide Web electronic publication. www.fishbase.org, version (03/2006). As of 2006, there are 223 genera.

Acarichthys Eigenmann 1912 Acaronia Myers 1940 Aequidens Eigenmann & Bray 1894 Alticorpus Stauffer & McKaye 1988 Altolamprologus Poll 1986 Amphilophus Agassiz, 1859 Anomalochromis Greenwood 1985 Apistogramma Regan 1913 Apistogrammoides Meinken 1965 Archocentrus Gill 1877 Aristochromis Trewavas, 1935 Astatoreochromis Pellegrin 1904 Astatotilapia Pellegrin 1904 Astronotus Swainson 1839 Aulonocara Regan 1922 Aulonocranus Regan 1920 Australoheros Rican & Kullander 2006 Baileychromis Poll 1986 Bathybates Boulenger 1898 Benitochromis Lamboj 2001 Benthochromis Poll 1986 Biotodoma Eigenmann & Kennedy 1903 Biotoecus Eigenmann & Kennedy 1903 Boulengerochromis Pellegrin 1904 Buccochromis Eccles & Trewavas 1989 Bujurquina Kullander 1986 Callochromis Regan 1920 Caprichromis Eccles & Trewavas 1989 Caquetaia Fowler 1945 Cardiopharynx Poll 1942 Chaetobranchopsis Steindachner, 1875 Chaetobranchus Heckel, 1840 Chalinochromis Poll 1974 Champsochromis Boulenger 1915 Cheilochromis Eccles & Trewavas 1989 Chetia Trewavas 1961 Chilochromis Boulenger 1902 Chilotilapia Boulenger 1908 Chromidotilapia Boulenger 1898 Cichla Bloch & Schneider 1801 Cichlasoma Swainson 1839 Cleithracara Kullander & Nijssen 1989 Copadichromis Eccles & Trewavas 1989 Corematodus Boulenger 1897 Crenicara Steindachner 1875 Crenicichla Heckel 1840 Ctenochromis Pfeffer 1893 Ctenopharynx Eccles & Trewavas 1989 Cunningtonia Boulenger 1906 Cyathochromis Trewavas 1935 Cyathopharynx Regan 1920 Cyclopharynx Poll 1948 Cynotilapia Regan 1922 Cyphotilapia Regan 1920 Cyprichromis Scheuermann 1977 Cyrtocara Boulenger 1902 Danakilia Thys van den Audenaerde 1969 Dicrossus Steindachner 1875 Dimidiochromis Eccles & Trewavas 1989 Diplotaxodon Trewavas 1935 Divandu Lamboj & Snoeks 2000 Docimodus Boulenger 1897 Eclectochromis Eccles & Trewavas 1989 Ectodus Boulenger 1898 Enterochromis Greenwood 1980 Eretmodus Boulenger 1898 Etia Schliewen & Stiassny 2003 Etroplus Cuvier 1830 Exochochromis Eccles & Trewavas 1989 Fossorochromis Eccles & Trewavas 1989 Gaurochromis Greenwood 1980 Genyochromis Trewavas 1935 Geophagus Heckel 1840 Gephyrochromis Boulenger 1901 Gnathochromis Poll 1981 Gobiocichla Kanazawa 1951 Grammatotria Boulenger 1899 Greenwoodochromis Poll 1983 Guianacara Kullander & Nijssen 1989 Gymnogeophagus Miranda Ribeiro 1918 Haplochromis Hilgendorf 1888 Haplotaxodon Boulenger 1906 Harpagochromis Greenwood 1980 Hemibates Regan 1920 Hemichromis Peters 1857 Hemitaeniochromis Eccles & Trewavas 1989 Hemitilapia Boulenger 1902 Herichthys Baird & Girard 1854 Herotilapia Pellegrin 1904 Heterochromis Regan 1922 Hoplarchus Kaup,1860 Hoplotilapia Hilgendorf 1888 Hypselecara Kullander 1986 Hypsophrys Agassiz 1859 Interochromis Yamaoka, Hori & Kuwamura 1988 Iodotropheus Oliver & Loiselle 1972 Iranocichla Coad 1982 Julidochromis Boulenger 1898 Katria Stiassny & Sparks 2006 Konia Trewavas 1972 Krobia Kullander & Nijssen 1989 Labeotropheus Ahl 1926 Labidochromis Trewavas 1935 Labrochromis Greenwood 1980 Laetacara Kullander 1986 Lamprologus Schilthuis 1891 Lepidiolamprologus Pellegrin 1904 Lestradea Poll 1943 Lethrinops Regan 1922 Lichnochromis Trewavas 1935 Limbochromis Greenwood 1987 Limnochromis Regan 1920 Limnotilapia Regan 1920 Lipochromis Greenwood 1980 Lithochromis Lippitsch & Seehausen 1998 Lobochilotes Boulenger 1915

Macropleurodus Regan 1922 Maylandia (Metriaclima) Meyer & Foerster 1984. For information on Maylandia vs. Metriaclima see: Maylandia. Mazarunia Kullander 1990 Mbipia Lippitsch & Seehausen 1998 Mchenga Stauffer & Konings, 2006 Melanochromis Trewavas, 1935 Mesonauta Günther, 1862 Microchromis Johnson 1975 Mikrogeophagus Meulengracht-Madson 1968 Myaka Trewavas 1972 Mylacochromis Greenwood 1980 Mylochromis Regan 1920 Naevochromis Eccles & Trewavas 1989 Nandopsis Gill, 1862 Nannacara Regan 1905 Nanochromis Pellegrin 1904 Neetroplus Günther, 1867 Neochromis Regan 1920 Neolamprologus Colombe & Allgayer 1985 Nimbochromis Eccles & Trewavas 1989 Nyassachromis Eccles & Trewavas 1989 Ophthalmotilapia Pellegrin 1904 Oreochromis Günther 1889 Orthochromis Greenwood 1954 Otopharynx Regan 1920 Oxylapia Kiener & Maugé 1966 Pallidochromis Turner 1994 Parachromis Agassiz 1859 Paracyprichromis Poll 1986 Paralabidochromis Greenwood 1956 Parananochromis Greenwood 1987 Paraneetroplus Regan 1905 Paratilapia Bleeker, 1868 Paretroplus Bleeker, 1868 Pelmatochromis Steindachner 1894 Pelvicachromis Thys van den Audenaerde 1968 Perissodus Boulenger 1898 Petenia Günther, 1862 Petrochromis Boulenger 1898 Petrotilapia Trewavas 1935 Pharyngochromis Greenwood 1979 Placidochromis Eccles & Trewavas 1989 Platytaeniodus Boulenger 1906 Plecodus Boulenger 1898 Prognathochromis Greenwood 1980 Protomelas Eccles & Trewavas 1989 Psammochromis Greenwood 1980 Pseudocrenilabrus Fowler 1934 Pseudosimochromis Nelissen 1977 Pseudotropheus Regan 1922 Pterochromis Trewavas 1973 Pterophyllum Heckel 1840 Ptychochromis Steindachner 1880 Ptyochromis Greenwood 1980 Pundamilia Seehausen & Lippitsch 1998 Pungu Trewavas 1972 Pyxichromis Greenwood 1980 Reganochromis Whitley 1929 Retroculus Eigenmann & Bray 1894 Rhamphochromis Regan 1922 Sargochromis Regan 1920 Sarotherodon Rppell 1852 Satanoperca Günther, 1862 Schubotzia Boulenger 1914 Schwetzochromis Poll 1948 Sciaenochromis Eccles & Trewavas 1989 Serranochromis Regan 1920 Simochromis Boulenger 1898 Spathodus Boulenger 1900 Steatocranus Boulenger 1899 Stigmatochromis Eccles & Trewavas 1989 Stomatepia Trewavas 1962 Symphysodon Heckel 1840 Taeniacara Myers 1935 Taeniochromis Eccles & Trewavas 1989 Taeniolethrinops Eccles & Trewavas 1989 Tahuantinsuyoa Kullander 1991 Tangachromis Poll 1981 Tanganicodus Poll 1950 Teleocichla Kullander 1988 Teleogramma Boulenger 1899 Telmatochromis Boulenger 1898 Theraps Günther, 1862 Thoracochromis Greenwood 1979 Thorichthys Meek 1904 Thysochromis Daget 1988 Tilapia Smith, 1840 See also: Tilapiine cichlids Tomocichla Regan 1908 Tramitichromis Eccles & Trewavas 1989 Trematocara Boulenger 1899 Trematocranus Trewavas 1935 Triglachromis Poll & Thys van den Audenaerde 1974 Tristramella Trewavas 1942 Tridontochromis Greenwood 1980 Tropheops Trewavas 1984 Tropheus Boulenger 1898 Tylochromis Regan 1920 Tyrannochromis Eccles & Trewavas 1989 Uaru Heckel 1840 Variabilichromis Colombe & Allgayer 1985 Vieja Fernandez-Yepez 1969 Xenochromis Boulenger 1899 Xenotilapia Boulenger 1899 Xystichromis Greenwood 1980

Images of cichlids

References

Further reading

• Barlow, G. W. (2000). The Cichlid fishes. Cambridge MA: Perseus Publishing.
• Cichlidae: ITIS Standard Report. (Integrated Taxonomic Information System: National Museum of Natural History, Washington, D.C., 2004-05-11). ITIS 169770

External links

• Lost African Lake Spawned Fish Diversity "Beyond Belief" Discussing the biodiversity of cichlids.
• Cichlid Room Companion
• FishBase.org The most current listing of cichlid taxonomy
• The Cichlid Fishes of Lake Malawi by Dr. Michael Oliver.
• An incomplete listing of cichlid genera and species, with phylogenetic context
• CICHLIDE38 The Cichlids of the lake Malawi localization of species and cartography