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'''Cichlids''' (pronounced “sick-lids”) are ] from the ] '''Cichlidae''' in the order ]. The family Cichlidae, a major family of perciform fish, is both large and diverse. Estimates of species range from 1200 to 1900, making it one of the three largest ] families.<ref>{{cite web|url=http://www.fishbase.org/Summary/FamilySummary.cfm?ID=349|title=Family Cichlidae - Cichlids |author=Froese, R. and D. Pauly. Editors.|publisher=FishBase|accessdate=2006-10-20}}</ref><ref>Kullander, S.O., 1998. A phylogeny and classification of the South American Cichlidae (Teleostei: Perciformes). p. 461-498. In: L.R. Malabarba, R.E. Reis, R.P. Vari, Z.M. Lucena and C.A.S. Lucena (eds.) Phylogeny and classification of neotropical fishes. Porto Alegre, Edipucrs</ref> They span a wide range of body sizes, from so-called dwarf species as small as 2.5 cm in length (e.g. ''] multifasciatus'' ) to much larger species approaching a metre in length (e.g. '']'' and '']''). As a group the cichlids exhibit a similarly wide diversity of body shapes, ranging from strongly laterally compressed species (such as '']'', '']'', and '']'') through to species that are cylindrical and highly elongate (such as '']'', '']'', '']'', and '']'').<ref>Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460</ref> 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 ] in terms of morphology, behaviour, and ecology.<ref>Helfman G., Collette B., & Facey D.: The Diversity of Fishes, Blackwell Publishing, pp 256-257, 1997, ISBN 0865422567</ref> '''Cichlids''' (pronounced “sick-lids”) are ] from the ] '''Cichlidae''' in the order ]. The family Cichlidae, a major family of perciform fish, is both large and diverse. Estimates of species range from 2000 to 2500, making it one of the three largest ] families.<ref>{{cite web|url=http://www.fishbase.org/Summary/FamilySummary.cfm?ID=349|title=Family Cichlidae - Cichlids |author=Froese, R. and D. Pauly. Editors.|publisher=FishBase|accessdate=2006-10-20}}</ref><ref>Kullander, S.O., 1998. A phylogeny and classification of the South American Cichlidae (Teleostei: Perciformes). p. 461-498. In: L.R. Malabarba, R.E. Reis, R.P. Vari, Z.M. Lucena and C.A.S. Lucena (eds.) Phylogeny and classification of neotropical fishes. Porto Alegre, Edipucrs</ref> They span a wide range of body sizes, from so-called dwarf species as small as 2.5 cm in length (e.g. ''] multifasciatus'' ) to much larger species approaching a metre in length (e.g. '']'' and '']''). As a group the cichlids exhibit a similarly wide diversity of body shapes, ranging from strongly laterally compressed species (such as '']'', '']'', and '']'') through to species that are cylindrical and highly elongate (such as '']'', '']'', '']'', and '']'').<ref>Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460</ref> 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 ] in terms of morphology, behaviour, and ecology.<ref>Helfman G., Collette B., & Facey D.: The Diversity of Fishes, Blackwell Publishing, pp 256-257, 1997, ISBN 0865422567</ref>


Some species, particularly the ]s are important food fishes, while others are valued game fish (eg. ''Cichla'' species). Many species are also highly valued in the ] trade.<ref>Chapman F. A.: Culture of Hybrid Tilapia: A Reference Profile. University of Florida Institute of Food and Agricultural Sciences Circular 1051, 1992 </ref><ref>Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460</ref> Cichlids are also the family of vertebrates with by far the highest number of ], most of these being from among the ] group.<ref>Reid G. M.,: Captive breeding for the conservation of cichlid fishes.'' Journal of Fish Biology'' '''37''', pp 157-166, 1990</ref> Cichlids are particularly well known for having ] into a large number of ] within in large lakes, particularly the ] lakes of ], , and ], and ]. <ref>Salzburger W, Mack T, Verheyen E, Meyer A (2005) Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes ''BMC Evolutionary Biology'' '''5''':17</ref><ref>Snoeks J. (ed.) (2004) The cichlid diversity of Lake Malawi/Nyasa/Niassa: identification, distribution and taxonomy. Cichlid Press, 2004, ISBN 0966825586</ref> Many cichlids that have been accidentally or deliberately released ] into freshwaters outside of their natural range have become nuisance species, for example ] in the southern United States.<ref>{{cite web|url=http://nis.gsmfc.org/nis_factsheet2.php?toc_id=195|title=Fact sheet for ''Oreochromis mossambicus'' (Peters, 1852)|author=Gulf States Marine Fisheries Commission|publisher=Gulf States Marine Fisheries Commission|accessdate=2006-10-20}}</ref> Some species, particularly the ]s are important food fishes, while others are valued game fish (eg. ''Cichla'' species). Many species are also highly valued in the ] trade.<ref>Chapman F. A.: Culture of Hybrid Tilapia: A Reference Profile. University of Florida Institute of Food and Agricultural Sciences Circular 1051, 1992 </ref><ref>Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460</ref> Cichlids are also the family of vertebrates with by far the highest number of ], most of these being from among the ] group.<ref>Reid G. M.,: Captive breeding for the conservation of cichlid fishes.'' Journal of Fish Biology'' '''37''', pp 157-166, 1990</ref> Cichlids are particularly well known for having ] into a large number of ] within in large lakes, particularly the ] lakes of ], , and ], and ]. <ref>Salzburger W, Mack T, Verheyen E, Meyer A (2005) Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes ''BMC Evolutionary Biology'' '''5''':17</ref><ref>Snoeks J. (ed.) (2004) The cichlid diversity of Lake Malawi/Nyasa/Niassa: identification, distribution and taxonomy. Cichlid Press, 2004, ISBN 0966825586</ref> Many cichlids that have been accidentally or deliberately released ] into freshwaters outside of their natural range have become nuisance species, for example ] in the southern United States.<ref>{{cite web|url=http://nis.gsmfc.org/nis_factsheet2.php?toc_id=195|title=Fact sheet for ''Oreochromis mossambicus'' (Peters, 1852)|author=Gulf States Marine Fisheries Commission|publisher=Gulf States Marine Fisheries Commission|accessdate=2006-10-20}}</ref>

Revision as of 03:37, 6 November 2006

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 2000 to 2500, making it one of the three largest vertebrate families. 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). 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.

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. 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. 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. 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.

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).

The particular features of cichlids that distinguish them from the other Labroidei include:

  • 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.

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. However, only a few cichlids are found primarily in brackish or salt water, most notably Etroplus maculatus, Etroplus suratensis, and Sarotherodon melanotheron.

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. This is not particularly unusual, having been observed among other groups of fishes, such as European cyprinids. 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.

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:

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.

Images of cichlids

female Apistogramma nijsseni
a pair of "Cichlasoma" amarum in Cancun lagoon, Mexico
Cichlids of Lake Malawi, Toronto Zoo, 2003


A substrate brooding female Parachromis managuense guards a clutch of eggs in the aquarium.
female Pelvicachromis pulcher
Variabilichromis moorii


References

  1. Froese, R. and D. Pauly. Editors. "Family Cichlidae - Cichlids". FishBase. Retrieved 2006-10-20. {{cite web}}: |author= has generic name (help)
  2. Kullander, S.O., 1998. A phylogeny and classification of the South American Cichlidae (Teleostei: Perciformes). p. 461-498. In: L.R. Malabarba, R.E. Reis, R.P. Vari, Z.M. Lucena and C.A.S. Lucena (eds.) Phylogeny and classification of neotropical fishes. Porto Alegre, Edipucrs
  3. Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460
  4. Helfman G., Collette B., & Facey D.: The Diversity of Fishes, Blackwell Publishing, pp 256-257, 1997, ISBN 0865422567
  5. Chapman F. A.: Culture of Hybrid Tilapia: A Reference Profile. University of Florida Institute of Food and Agricultural Sciences Circular 1051, 1992
  6. Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460
  7. Reid G. M.,: Captive breeding for the conservation of cichlid fishes. Journal of Fish Biology 37, pp 157-166, 1990
  8. Salzburger W, Mack T, Verheyen E, Meyer A (2005) Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes BMC Evolutionary Biology 5:17
  9. Snoeks J. (ed.) (2004) The cichlid diversity of Lake Malawi/Nyasa/Niassa: identification, distribution and taxonomy. Cichlid Press, 2004, ISBN 0966825586
  10. Gulf States Marine Fisheries Commission. "Fact sheet for Oreochromis mossambicus (Peters, 1852)". Gulf States Marine Fisheries Commission. Retrieved 2006-10-20.
  11. Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460
  12. Froese, R. and D. Pauly. Editors. "Family Cichlidae - Cichlids". FishBase. Retrieved 2006-10-20. {{cite web}}: |author= has generic name (help)
  13. Gulf States Marine Fisheries Commission. "Non-Native Aquatic Species Summaries". Gulf States Marine Fisheries Commission. Retrieved 2006-10-24.
  14. ABC Far North Queensland. "Tilapia :: Far North Queensland". Retrieved 2006-10-25.
  15. Loiselle P. V.,: The Cichlid Aquarium, Voyageur Press, ISBN 1564651460
  16. Frank Schäfer (2005). Brackish-Water Fishes. Aqualog. ISBN 3-936027-82-X (English), ISBN 3-936027-81-1 (German).
  17. Smith, P. F., Konings, A., and Kornfield I.: Hybrid origin of a cichlid population in Lake Malawi: implications for genetic variation and species diversity. Molecular Ecology 12, pp 2497–2504, 2003
  18. Wood, A. B., and Jordan, D. R.: Fertility of roach × bream hybrids, Rutilus rutilus (L.) × Abramis brama (L.), and their identification. Journal of Fish Biology 30, pp 249-261, 1987
  19. Chapman F. A.: Culture of Hybrid Tilapia: A Reference Profile. University of Florida Institute of Food and Agricultural Sciences Circular 1051, 1992
  20. Matt Clarke. "Frequently asked questions on Parrot cichlids". Practical Fishkeeping. Retrieved 2006-10-20.

Further reading

External links

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