|Common freshwater angelfish,
Cichlids // are fish from the family Cichlidae in the order Perciformes. Cichlids are members of a suborder known as Labroidei, along with the wrasses (Labridae), damselfishes (Pomacentridae), and surfperches (Embiotocidae). This family is both large and diverse. At least 1,650 species have been scientifically described, making it one of the largest vertebrate families. New species are discovered annually, and many species remain undescribed. The actual number of species is therefore unknown, with estimates varying between 2,000 and 3,000. Cichlids are popular freshwater fish kept in the home aquarium.
- 1 Description
- 2 Anatomy and appearance
- 3 Taxonomy
- 4 Distribution and habitat
- 5 Ecology
- 6 Reproduction
- 7 Speciation
- 8 Population status
- 9 Food and game fish
- 10 Aquarium fish
- 11 Hybrids and selective breeding
- 12 Genera
- 13 Images of cichlids
- 14 References
- 15 Further reading
- 16 External links
Cichlids span a wide range of body sizes, from species as small as 2.5 cm (0.98 in) in length (e.g., female Neolamprologus multifasciatus) to much larger species approaching 1 m (3.3 ft) in length (e.g. Boulengerochromis and Cichla). As a group, cichlids exhibit a similar diversity of body shapes, ranging from strongly laterally compressed species (such as Altolamprologus, Pterophyllum, and Symphysodon) to species that are cylindrical and highly elongated (such as Julidochromis, Teleogramma, Teleocichla, Crenicichla, and Gobiocichla). Generally, however, cichlids tend to be of medium size, ovate in shape, and slightly laterally compressed, and generally similar to the North American sunfishes in morphology, behavior, and ecology.
Many cichlids, particularly tilapia, are important food fishes, while others are valued game fish (e.g. Cichla species). The family also includes many familiar aquarium fish, including the angelfish, oscars, and discus. Cichlids have the largest number of endangered species among vertebrate families, most in the haplochromine group. Cichlids are particularly well known for having evolved rapidly into a large number of closely related but morphologically diverse species within large lakes, particularly Tanganyika, Victoria, Malawi, and Edward. Their diversity in the African Great Lakes is important for the study of speciation in evolution. Many cichlids introduced into waters outside of their natural range have become nuisances.
Anatomy and appearance
Cichlids share 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 labor between the "true jaws" (mandibles) and the "pharyngeal jaws". Cichlids are efficient and often highly specialized feeders that capture and process a very wide variety of food items. This is assumed to be one reason why they are so diverse. Cichlids vary in body shape, ranging from compressed and disc-shaped (such as Symphysodon and Heros), to triangular (such as Pterophyllum and Uaru) to elongated and cylindrical (such as Crenicichla and Biotecus).
The features that distinguish them from the other families in Labroidei include:
- A single nostril on each side of the forehead, instead of two
- No bony shelf below the orbit of the eye
- Division of the lateral line organ 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's left-side exit from the stomach instead of its right side as in other Labroidei
Kullander (1998) recognizes eight subfamilies of cichlids: the Astronotinae, Cichlasomatinae, Cichlinae, Etroplinae, Geophaginae, Heterochromidinae, Pseudocrenilabrinae, and Retroculinae. A ninth subfamily, Ptychochrominae, was later recognized by Sparks and Smith. Cichlid taxonomy is still debated, and classification of genera cannot yet be definitively given. A comprehensive system of assigning species to monophyletic genera is still lacking, and there is not complete agreement on what genera should be recognized in this family.
As an example of the classification problems, Kullander placed the African genus Heterochromis phylogenetically within neotropical cichlids, although later papers concluded otherwise. Other problems center upon the identity of the putative common ancestor for the Lake Victoria superflock, and the ancestral lineages of Tanganyikan cichlids.
Comparisons between a morphologically-based phylogeny and analyses of gene loci produce differences at the genus level. There remains a consensus that the Cichlidae as a family is monophyletic.
One problem that transformed cichlid taxonomy is related to dentition, which had been used as a classifying characteristic. In many cichlids, tooth shape changes with age, due to wear, and cannot be relied upon. Genome sequencing and other technologies transformed cichlid taxonomy.
Distribution and habitat
Cichlids are one of the largest vertebrate families in the world. They are most diverse in Africa and South America. Africa alone is estimated to host at least 1,600 species. Central America and Mexico have about 120 species, as far north as the Rio Grande in southern Texas. Madagascar has its own distinctive species (Katria, Oxylapia, Paratilapia, Paretroplus, Ptychochromis, and Ptychochromoides), only distantly related to those on the African mainland. Native cichlids are largely absent in Asia, except for 9 species in Israel, Lebanon, and Syria (Astatotilapia flaviijosephi, Oreochromis aureus, O. niloticus, Sarotherodon galilaeus, Coptodon zillii, and Tristramella spp.), one in Iran (Iranocichla), and three in India and Sri Lanka (Etroplus). If disregarding Trinidad and Tobago (where the few native cichlids are members of genera that are widespread in the South American mainland), the three species from the genus Nandopsis are the only cichlids from the Antilles in the Caribbean, specifically Cuba and Hispaniola. Europe, Australia, Antarctica, and North America north of the Rio Grande drainage have no native cichlids, although in Florida, Mexico, Japan and northern Australia, feral populations of cichlids have become established as exotics.
Although most cichlids are found at relatively shallow depths, several exceptions do exist. These include species such as Alticorpus macrocleithrum and Pallidochromis tokolosh down to 150 m (490 ft) below the surface in Lake Malawi, and the whitish (nonpigmented) and blind Lamprologus lethops, which is believed to live as deep as 160 m (520 ft) below the surface in the Congo River.
Cichlids are less commonly found in brackish and saltwater habitats, though many species tolerate brackish water for extended periods; Cichlasoma urophthalmus, for example, is equally at home in freshwater marshes and mangrove swamps, and lives and breeds in saltwater environments such as the mangrove belts around barrier islands. Several species of Tilapia, Sarotherodon, and Oreochromis are euryhaline and can disperse along brackish coastlines between rivers. Only a few cichlids, however, inhabit primarily brackish or salt water, most notably Etroplus maculatus, Etroplus suratensis, and Sarotherodon melanotheron. The perhaps most extreme habitats for cichlids are the warm hypersaline lakes where the members of the genera Alcolapia and Danakilia are found. Lake Abaeded in Eritrea encompasses the entire distribution of D. dinicolai, and its temperature ranges from 29 to 45 °C (84 to 113 °F).
With the exception of the species from Cuba, Hispaniola, and Madagascar, cichlids have not reached any oceanic island and have a predominantly Gondwanan distribution, showing the precise sister relationships predicted by vicariance: Africa-South America and India-Madagascar. The dispersal hypothesis, in contrast, requires cichlids to have negotiated thousands of kilometers of open ocean between India and Madagascar without colonizing any other island or, for that matter, crossing the Mozambique Channel to Africa. Although the vast majority of Malagasy cichlids are entirely restricted to fresh water, Ptychochromis grandidieri and Paretroplus polyactis are commonly found in coastal brackish water and they are apparently salt tolerant, as is also the case for Etroplus maculatus and E. suratensis from India and Sri Lanka.
|This article needs additional citations for verification. (October 2014) (Learn how and when to remove this template message)|
Other cichlids are predatory and eat little or no 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 specialized snail-eater, while Pungu maclareni feeds on sponges. A number of cichlids feed on other fish, either entirely or in part. Crenicichla species are stealth-predators that lunge from concealment at passing small fish, while Rhamphochromis species are open-water pursuit predators that chase down their prey. Paedophagous cichlids such as the 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 feeding strategies are those of Corematodus, Docimodus evelynae, Plecodus, Perissodus, and Genyochromis spp., which feed on scales and fins of other fishes, a behavior known as lepidophagy, along with the death-mimicking behaviour of Nimbochromis and Parachromis species, which lay motionless, luring small fish to their side prior to ambush.
This variety of feeding styles has helped cichlids to inhabit similarly varied habitats. Its pharyngeal teeth (teeth in the throat) afford cichlids so many "niche" feeding strategies, because the jaws pick and hold food, while the pharyngeal teeth crush the prey.
Cichlids have highly organized breeding activities.
Communal parental care, where multiple monogamous pairs care for a mixed school of young have also been observed in multiple cichlid species, including Amphilophus citrinellus, Etroplus suratensis, and Tilapia rendalli. Comparably, the fry of Neolamprologus brichardi, a species that commonly lives in large groups, are protected not only by the adults, but also by older juveniles from previous spawns. Several cichlids, including discus (Symphysodon spp.), some Amphilophus species, Etroplus, and Uaru species, feed their young with a skin secretion from mucous glands.
The species Neolamprologus pulcher uses a cooperative breeding system, in which one breeding pair has many helpers which are subordinate to the dominant breeders.
Parental care falls into one of four categories: substrate or open brooders, secretive cave brooders (also known as guarding speleophils), and at least two types of mouthbrooders, ovophile mouthbrooders and larvophile mouthbrooders.
Open- or substrate-brooding cichlids lay their eggs in the open, on rocks, leaves, or logs. Examples of open-brooding cichlids include Pterophyllum and Symphysodon species and Anomalochromis thomasi. Male and female parents usually engage in differing brooding roles. Most commonly, the male patrols the pair's territory and repels intruders, while the female fans water over the eggs, removing the infertile and leading the fry while foraging. However, both sexes are able to perform the full range of parenting behaviours.
Secretive cave-spawning cichlids lay their eggs in caves, crevices, holes, or discarded mollusc shells, frequently attaching the eggs to the roof of the chamber. Examples include Pelvicachromis spp., Archocentrus spp., and Apistogramma spp. Free-swimming fry and parents communicate in captivity and in the wild. Frequently, this communication is based on body movements, such as shaking and pelvic fin flicking. In addition, open- and cave-brooding parents assist in finding food resources for their fry. Multiple neotropical cichlid species perform leaf-turning and fin-digging behaviors.
Ovophile mouthbrooders incubate their eggs in their mouths as soon as they are laid, and frequently mouthbrood free-swimming fry for several weeks. Examples include many East African Rift lakes (Lake Malawi, Lake Tanganyika and Lake Victoria) endemics, e.g.: Maylandia, Pseudotropheus, Tropheus, and Astatotilapia burtoni, along with some South American cichlids such as Geophagus steindachneri.
Larvophile mouthbrooders lay eggs in the open or in a cave and take the hatched larvae into the mouth. Examples include some variants of Geophagus altifrons, and some Aequidens, Gymnogeophagus, and Satanoperca, as well as Oreochromis mossambicus and Oreochromis niloticus. Mouthbrooders, whether of eggs or larvae, are predominantly females. Exceptions that also involve the males include eretmodine cichlids (genera Spathodus, Eretmodus, and Tanganicodus), some Sarotherodon species, Chromidotilapia guentheri, and some Aequidens species. Rare paternal mouthbrooding occurs, for example, in Sarotherodon melanotheron. This method appears to have evolved independently in several groups of African cichlids.
Cichlids mate either monogamously or polygamously. The mating system of a given cichlid species is not consistently associated with its brooding system. For example, although most monogamous cichlids are not mouthbrooders, Chromidotilapia, Gymnogeophagus, Spathodus and Tanganicodus are all monogamous mouthbrooders. In contrast, numerous open- or cave-spawning cichlids are polygamous; examples include Apistogramma, Lamprologus, Nannacara, and Pelvicachromis.
Cichlids provide scientists with a unique perspective of speciation, having become extremely diverse in the more recent geological past. It is widely believed that one of the contributing factors to their diversification are the various forms of prey processing displayed by cichlid pharyngeal jaw apparatus. These different jaw apparatus allow for a broad range of feeding strategies including: algae scraping, snail crushing, planktivores, piscivores, and insectivores. Some cichlids can also show phenotypic plasticity in their pharyngeal jaws, which can also help lead to speciation. In response to different diets or food scarcity, members of the same species can display different jaw morphologies that are better suited to different feeding strategies. As species members begin to concentrate around different food sources and continue their life cycle, they most likely spawn with like individuals. This can reinforce the jaw morphology and given enough time, create new species. This can happen through allopatric speciation, when they concentrate on different food sources in different areas, or possibly through sympatric speciation. This is one of the most interesting aspects of cichlid diversification, there exists a strong possibility that they can provide us with evidence of sympatric speciation. In a crater lake in Nicaragua called Lake Apoyo, there is a species of cichlid, Amphilophus zaliosus, that very may well have speciated through sympatric speciation. A. zaliosus, its sister species Amphilophus citrinellus, and the lake itself display many of the criteria needed for sympatric speciation.
In 2010, the International Union for Conservation of Nature classified 184 species as vulnerable, 52 as endangered, and 106 as critically endangered. At present, the IUCN only lists Yssichromis sp. nov. "argens" as extinct in the wild, and six species are listed as entirely extinct, but it is acknowledged that many more possibly belong in these categories (for example, Haplochromis aelocephalus, H. apogonoides, H. dentex, H. dichrourus and numerous other members of the genus Haplochromis have not been seen since the 1980s, but are maintained as Critically Endangered in the small chance that tiny –but currently unknown– populations survive).
Because of the introduced Nile perch (Lates niloticus) and water hyacinth, deforestation that led to water siltation, and overfishing, many Lake Victoria species have been wiped out or drastically reduced. By around 1980, lake fisheries yielded only 1% cichlids, a drastic decline from 80% in earlier years.
About two-thirds of endemic cichlids (about 300 species), especially bottom feeders, became endangered or extinct. Some survivors have adapted by becoming smaller or hybridizing with other species. Satellite lakes, such as Lake Edward and Lake Kyoga, have not been as strongly affected, however, and harbor an array of similar species.
Food and game fish
Although cichlids are mostly small- to medium-sized, many are notable as food and game fishes. With few thick rib bones and tasty flesh, artisan fishing is not uncommon in Central America and South America, as well as areas surrounding the African rift lakes.
The most important food cichlids, however, are the tilapiines of North Africa. Fast growing, tolerant of stocking density, and adaptable, tilapiine species have been introduced and farmed extensively in many parts of Asia and are increasingly common aquaculture targets elsewhere.
Unlike those carnivorous fish, tilapia can feed on algae or any plant-based food. This reduces the cost of tilapia farming, reduces fishing pressure on prey species, avoids concentrating toxins that accumulate at higher levels of the food chain, and makes tilapia the preferred "aquatic chickens" of the trade.
Many large cichlids are popular game fish. The peacock bass (Cichla species) of South America is one of the most popular sportfish. It was introduced in many waters around the world.[where?] In Florida, this fish generates millions of hours of fishing and sportfishing revenue of more than US$8 million a year. Other cichlids preferred by anglers include the oscar, Mayan cichlid (Cichlasoma urophthalmus), and jaguar guapote (Parachromis managuensis).
The most common species in hobbyist aquaria is Pterophyllum scalare from the Amazon River basin in tropical South America, known in the trade as the "angelfish". Other popular or readily available species include the oscar (Astronotus ocellatus), convict cichlid (Archocentrus nigrofasciatus) and discus fish (Symphysodon).
Hybrids and selective breeding
Some cichlids readily hybridize with related species, both in the wild and under artificial conditions. Other groups of fishes, such as European cyprinids, also hybridize. Unusually, cichlid hybrids have been put to extensive commercial use, in particular for aquaculture and aquaria. The hybrid red strain of tilapia, for example, is often preferred in aquaculture for its rapid growth. Tilapia hybridization can produce all-male populations to control stock density or prevent reproduction in ponds.
The most common aquarium hybrid is perhaps the blood parrot cichlid, which is a cross of several species, especially from species in the genus Amphilophus. (There are many hypotheses, but the most likely is: [ Amphilophus Labiatus x ([Vieja Synspillus] x [Heros Severus])) With a Triangular-shaped mouth, an abnormal spine, and an occasionally missing caudal fin (known as the "love heart" parrot cichlid), the fish is controversial among aquarists. Some have called blood parrot cichlids "the Frankenstein monster of the fish world". Another notable hybrid, the flowerhorn cichlid, was very popular in some parts of Asia from 2001 until late 2003, and is believed to bring good luck to its owner. The popularity of the flowerhorn cichlid declined in 2004. Owners released many specimens into the rivers and canals of Malaysia and Singapore, where they threaten endemic communities.
Numerous cichlid species have been selectively bred to develop ornamental aquarium strains. The most intensive programs have involved angelfish and discus, and many mutations that affect both coloration and fins are known. Other cichlids have been bred for albino, leucistic, and xanthistic pigment mutations, including oscars, convict cichlid and Pelvicachromis pulcher. Both dominant and recessive pigment mutations have been observed. In convict cichlids, for example, a leucistic coloration is recessively inherited, while in Oreochromis niloticus niloticus, red coloration is caused by a dominant inherited mutation.
This selective breeding may have unintended consequences. For example, hybrid strains of Mikrogeophagus ramirezi have health and fertility problems. Similarly, intentional inbreeding can cause physical abnormalities, such as the notched phenotype in angelfish.
Images of cichlids
The Nile tilapia (Oreochromis niloticus) is farmed extensively as food fish in many parts of the world.
The angelfish (Pterophyllum scalare) has long been commercially bred for the aquarium trade.
A discus (Symphysodon spp.) is guarding its eggs. Advanced broodcare is one of the defining characteristics of cichlids.
The Texas cichlid (Herichthys cyanoguttatus) is the only cichlid native to the United States.
The red terror cichlid is a highly aggressive species from the rivers of Northeast South America.
- Stiassny, M.L.J.; Jensen, J.S. (1987). "Labroid intrarelationships revisited: morphological complexity, key innovations, and the study of comparative diversity". Bulletin of the Museum of Comparative Zoology 151: 269–319.
- "List of Nominal Species of Cichlidae, in Froese, Rainer, and Daniel Pauly, eds. (2012). FishBase,". February 2012.
- Stiassny, M., G. G. Teugels & C. D. Hopkins (2007). The Fresh and Brackish Water Fishes of Lower Guinea, West-Central Africa - Vol. 2. Musée Royal de l'Afrique Centrale. p. 269. ISBN 978-90-74752-21-3.
- Loiselle, P.V. (1994). The Cichlid Aquarium. Tetra Press. ISBN 1-56465-146-0.
- Helfman G.; Collette B.; Facey D. (1997). The Diversity of Fishes. Blackwell Publishing, Inc. pp. 256–257. ISBN 0-86542-256-7.
- Chapman, F. A. (1992). "Culture of Hybrid Tilapia: A Reference Profile" (PDF). Circular 1051. University of Florida Institute of Food and Agricultural Sciences.
- Reid, G. M. (December 1990). "Captive breeding for the conservation of cichlid fishes" (fee required). Journal of Fish Biology 37: 157–166. doi:10.1111/j.1095-8649.1990.tb05031.x.
- Salzburger W.; Mack T.; Verheyen E.; Meyer A. (2005). "Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes" (PDF). BMC Evolutionary Biology 5 (17): 17. doi:10.1186/1471-2148-5-17. PMC 554777. PMID 15723698.
- Snoeks, J. (ed.) (2004). The cichlid diversity of Lake Malawi/Nyasa/Niassa: identification, distribution and taxonomy. Cichlid Press. ISBN 0-9668255-8-6.
- Kornfield, Irv; Smith, Peter (November 2000). "African Cichlid Fishes: Model Systems for Evolutionary Biology". Annual Review of Ecology and Systematics 31: 163–196. doi:10.1146/annurev.ecolsys.31.1.163.
- Gulf States Marine Fisheries Commission. "Fact sheet for Oreochromis mossambicus (Peters, 1852)". Gulf States Marine Fisheries Commission. Retrieved 20 October 2006.
- Nelson, Joseph, S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
- Froese, Rainer, and Daniel Pauly, eds. (2006). "Cichlidae" in FishBase. April 2006 version.
- Kullander, S.O. (1998). "A phylogeny and classification of the South American Cichlidae (Teleostei: Perciformes)". In L.R. Malabarba; R.E. Reis; R.P. Vari; Z.M. Lucena; C.A.S. Lucena. Phylogeny and classification of neotropical fishes. Porto Alegre: EDIPUCRS. pp. 461–498. ISBN 978-85-7430-035-1.
- Sparks, J.S.; Smith, W.L. (2004). "Phylogeny and biogeography of cichlid fishes (Teleostei: Perciformes: Cichlidae)". Cladistics 20 (6): 501–517. doi:10.1111/j.1096-0031.2004.00038.x.
- Phylogeny of major groups of cichlids
- Multilocus Phylogeny of Cichlid Fishes (Pisces: Perciformes): Evolutionary Comparison of Microsatellite and Single-Copy Nuclear Loci by Streelman, Zardoya, Meyer and Karl (1998) (Mol. Biol. Evol. 15(7):798–808. 1998, paper available as PDF here
- Stiassny, 1991
- maximum-parsimony bootstrap consensus trees and majority-rule trees and other similar phylogenetic trees
- From the various nuclear and mitochondrial DNA analyses in this and other papers
- Further insights into the attractiveness of Cichlid taxonomy as a fertile area of research is given by the paper The species flocks of East African cichlid fishes: recent advances in molecular phylogenetics and population genetics by Salzburger and Meyer (Naturwissenschaften (2004) 91:277–290, paper available as PDF here), in which the advances made in the analysis of the phylogeny of the Lake Victoria superflock (among other East African Cichlids) is discussed in depth.
- Highlighted by Dr Humphry Greenwood of the Natural History Museum, London, in a paper in 1977 (cited in TFH magazine, August 1977, with a follow up letter by Dr Greenwood in the November 1977 issue complaining about poor reportage of his work).
- Koehn, J.D.; MacKenzie, R.F. (2004). "Priority management actions for alien freshwater fish species in Australia" (PDF). New Zealand Journal of Marine and Freshwater Research 38 (3): 457–472. doi:10.1080/00288330.2004.9517253. Archived from the original (PDF) on 28 October 2004. Retrieved 19 April 2007.
- Boruchowitz, D. E. (2006). Guide to Cichlids. T.F.H. Publications. ISBN 0-7938-0584-8.
- ABC Far North Queensland. "Tilapia :: Far North Queensland". Archived from the original on 17 October 2007. Retrieved 19 April 2007.
- Froese, R.; D. Pauly (eds.). "Archocentrus nigrofasciatus, Convict cichlid". FishBase. Retrieved 29 March 2007.
- Yamamoto, M.N.; Tagawa, A.W. (2000). Hawai'i's native and exotic freshwater animals. Honolulu, Hawaii: Mutual Publishing. p. 200.
- Page, L.M.; Burr, B.M. (1991). A field guide to freshwater fishes of North America north of Mexico. Boston: Houghton Mifflin Company. p. 432. ISBN 0-395-35307-6.
- University of Southern Mississippi/College of Marine Sciences/Gulf Coast Research Laboratory (3 August 2005). "Fact Sheet for Tilapia zilli (Gervais, 1848)". Gulf States Marine Fisheries Commission. Retrieved 10 February 2007.
- Fuller, Pam L.; Leo G. Nico (11 October 2002). "Nonindigenous Fishes of Florida - With a Focus on South Florida". U.S. Department of the Interior, U.S. Geological Survey, Center for Coastal Geology. Retrieved 10 February 2007.
- Froese, Rainer and Pauly, Daniel, eds. (2006). "Alticorpus macrocleithrum" in FishBase. April 2006 version.
- Froese, Rainer and Pauly, Daniel, eds. (2006). "Pallidochromis tokolosh" in FishBase. April 2006 version.
- Norlander, Britt (20 April 2009). Rough waters: one of the world's most turbulent rivers is home to a wide array of fish species. Now, large dams are threatening their future. Science World
- Frank Schäfer (2005). Brackish-Water Fishes. Aqualog. ISBN 978-3-936027-82-2.
- Stiassny, de Marchi & Lamboj (2010). A new species of Danakilia (Teleostei, Cichlidae) from Lake Abaeded in the Danakil Depression of Eritrea (East Africa). Zootaxa 2690: 43–52.
- Chakrabarty, P., Cichlid Biogeography: Comment and Review, Fish and Fisheries, Volume 5, Pages 97-119, 2004
- Stiassny, M., and Sparks, J. S. (2006). Phylogeny and Taxonomic Revision of the endemic Malagasy genus Ptychochromis (Teleostei: Cichlidae), with the description of five new species and a diagnosis for Katria, new genus. American Museum Novitates 3535.
- Sparks, J. S. (2008). Phylogeny of the Cichlid Subfamily Etroplinae and Taxonomic Revision of the Malagasy Cichlid Genus Paretroplus (Teleostei: Cichlidae). Bulletin of the American Museum of Natural History Number 314: 1-151
- Froese, Rainer and Pauly, Daniel, eds. (2006). "Etroplus maculatus" in FishBase. April 2006 version.
- Froese, Rainer and Pauly, Daniel, eds. (2006). "Etroplus suratensis" in FishBase. April 2006 version.
- Ribbink, A.J.; Lewis, D.S.C. (1982). "Melanochromis crabro sp. nov.: a cichlid fish from Lake Malawi which feeds on ectoparasites and catfish eggs". Netherlands Journal of Zoology 32 (1): 72–87. doi:10.1163/002829682X00058..
- Oliver, M.K. (18 November 1999). "Rhamphochromis esox". malawicichlids.com: The Cichlid Fishes of Lake Malawi. Retrieved 19 April 2007.
- Ribbink, A.J.; Ribbink, A.C. (1997). "Paedophagia among cichlid fishes of Lake Victoria and Lake Malawi/Nyasa". South African Journal of Science 93: 509–512.
- McKaye, K.R.; Kocher, T. (1983). "Head ramming behaviour by three paedophagous cichlids in Lake Malawi, Africa". Animal Behaviour 31: 206–210. doi:10.1016/S0003-3472(83)80190-0.
- Wilhelm, W. (1980). "The disputed feeding behavior of a paedophagous haplochromine cichlid (Pisces) observed and discussed". Behaviour 74 (3): 310–322. doi:10.1163/156853980X00528.
- Konings, A. (2007). "Paedophagy in Malawi cichlids". Cichlid News 16: 28–32.
- Trewavas, E. (1947). "An example of "mimicry" in fishes". Nature 160 (4056): 120. doi:10.1038/160120a0.
- Eccles, D.H.; D.S.C. Lewis (1976). "A taxonomic study of the genus Docimodus Boulenger (Pisces, Cichlidae) a group of fishes with unusual feeding habits from Lake Malawi". Zoological Journal of the Linnean Society 58 (2): 165–172. doi:10.1111/j.1096-3642.1976.tb00826.x.
- Nshombo, M. (1991). "Occasional egg-eating by the scale-eater Plecodus straeleni (Cichlidae) of Lake Tanganyika". Environmental Biology of Fishes 31 (2): 207–212. doi:10.1007/BF00001022.
- Tobler, M. (2005). "Feigning death in the Central American cichlid Parachromis friedrichsthalii". Journal of Fish Biology 66 (3): 877–881. doi:10.1111/j.0022-1112.2005.00648.x.
- McKaye, K.R. (1981). "Field observation on death feigning: a unique hunting behavior by the predatory cichlid, Haplochromis livingstoni, of Lake Malawi". Environmental Biology of Fishes 6 (3–4): 361–365. doi:10.1007/BF00005766.
- McKaye, K.R.; N.M. McKaye (1977). "Communal Care and Kidnapping of Young by Parental Cichlids". Evolution 31 (3): 674–681. doi:10.2307/2407533. JSTOR 2407533.
- Ward, J.A.; R.L. Wyman (1977). "Ethology and ecology of cichlid fishes of the genus Etroplus in Sri Lanka: preliminary findings". Environmental Biology of Fishes 2 (2): 137–145. doi:10.1007/BF00005369.
- Ribbink, A.J.; A.C. Marsh, and B.A. Marsh (1981). "Nest-building and communal care of young by Tilapia rendalli dumeril (pisces, cichlidae) in Lake Malawi". Environmental Biology of Fishes 6 (2): 219–222. doi:10.1007/BF00002787.
- Steeves, Greg. Neolamprologus brichardi. africancichlids.net. Accessed 2008-04-08
- Riehl, Rüdiger. Editor.; Baensch, HA (1996). Aquarium Atlas. Germany: Tetra Press. ISBN 3-88244-050-3.
- Balon, E.K. (1975). "Reproductive guilds of fishes: a proposal. and definition". Journal of the Fisheries Research Board of Canada 32 (6): 821–864. doi:10.1139/f75-110.
- Keenleyside, M.H.A. (1991). "Parental Care". Cichlid Fishes: behaviour, ecology and evolution. London: Chapman and Hall. pp. 191–208. ISBN 0-412-32200-5.
- Coleman, R. (January 1999). "Mysterious mouthbrooders". Cichlid News: 32–33.
- Kishida, M.; J.L. Specker (2000). "Paternal Mouthbrooding in the Black-Chinned Tilapia, Sarotherodon melanotheron (Pisces: Cichlidae): Changes in Gonadal Steroids and Potential for Vitellogenin Transfer to Larvae". Hormones and Behavior 37 (1): 40–48. doi:10.1006/hbeh.1999.1556. PMID 10712857.
- Martin, E.; M. Taborsky (1997). "Alternative male mating acttics in a cichlid, Pelvicachromis pulcher: a comparison of reproductive effort and success". Behavioral Ecology and Sociobiology 41 (5): 311–319. doi:10.1007/s002650050391.
- Albertson, R. C.; Markert, J. A.; Danley, P. D.; Kocher, T. D. (1999). "Phylogeny of a rapidly evolving clade: The cichlid fishes of Lake Malawi, East Africa". PNAS 96: 5107–5110. doi:10.1073/pnas.96.9.5107.
- Muschick, M.; Barluenga, M.; Salzburger, W.; Meyer, A. (2011). "Adaptive phenotypic plasticity in the Midas cichlid fish pharyngeal jaw and its relevance in adaptive radiation". BMC Evolutionary Biology 11: 116. doi:10.1186/1471-2148-11-116.
- Barluenga, M.; Meyer, A.; Muschick, M.; Salzburger, W.; Stolting, K. N. (2006). "Sympatric speciation in Nicaraguan crater lake cichlid fish". Nature 439: 719–23. doi:10.1038/nature04325. PMID 16467837.
- IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. Downloaded on 26 April 2011.
- Barlow, G. W. (2000). The Cichlid Fishes. Cambridge, MA: Perseus Publishing. ISBN 0-7382-0376-9.
- Kaufman L (1996) Haplochromis latifasciata. In: IUCN 2006. 2006 IUCN Red List of Threatened Species.
- De Silva, S.S; Subasinghe, R.P.; Bartley, D.M.; Lowther, A. :Tilapias as Alien Aquatics in Asia and the Pacific: A Review. FAO Fisheries Technical Paper. No. 453, 2004. 
- Florida Fish and Wildlife Conservation Commission. "Fact Exotic Freshwater Fishes". Retrieved 18 March 2007.
- Sands D (1994) A fishkeepers guide to Central American cichlids. Tetra Press. Belgium pg 59-60.
- Mills D (1993) Aquarium Fish Harper Collins ISBN 0-7322-5012-9
- Konings A (1997) Back to nature guide to Malawi Cichlids Druckhaus Beltz, Germany. p. 13-23
- Leibel WS (1993) A fishkeepers guide to South American cichlids. Tetra Press. Belgium pg 12-14.
- 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 
- 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
- Matt Clarke. "Frequently asked questions on Parrot cichlids". Practical Fishkeeping. Archived from the original on 26 September 2007. Retrieved 20 October 2006.
- "It's The Frankenstein Monster Of The Fish World: The Blood Parrot!". AquaFriend.com. 27 October 2002. Retrieved 5 December 2006.
- Arnold W (2003) Singapore's 'lucky' pet Luohan can outnumber people in homes. International Herald Tribune. July 1.
- Crayfish the latest fad among pet lovers New Straits Times (Malaysia) (2004) 3 September
- Flower Horn: Joy in homes, a pest in rivers. New Straits Times (Malaysia) (2004) 14 July.
- Norton, J (1982). "Angelfish genetics". Freshwater And Marine Aquarium magazine 5: 4.
- Koh, TL; Khoo, G; Fan, LQ; Phang, VPE (1999). "Genetic diversity among wild forms and cultivated varieties of Discus (Symphysodon spp.) as revealed by Random Amplified Polymorphic DNA (RAPD) fingerprinting". Aquaculture 173: 485–497. doi:10.1016/s0044-8486(98)00478-5.
- Kornfield I (1991) Genetics. In: Cichlid Fishes: behaviour, ecology and evolution Ed. Keenleyside MHA. Chapman and Hall, London. p. 109-115.
- Itzkovich, J; Rothbard, S; Hulata, G (1981). "Inheritance of pink body colouration in Cichlasoma nigrofasciatum Günther (Pisces, Cichlidae)". Genetica 55: 15–16. doi:10.1007/bf00133997.
- McAndrew, CJ; Roubal, FR; Roberts, RJ; Bullock, AM; McEwan, IM (1988). "The genetics and history of red, blond, and associated color variants in Oreochromis niloticus". Genetica 76: 127–137. doi:10.1007/bf00058811.
- Linke H, Staeck L (1994) American cichlids I: Dwarf Cichlids. A handbook for their identification, care and breeding. Tetra Press. Germany. ISBN 1-56465-168-1
- Norton J (1994) Notched - An Angelfish Deformity Freshwater And Marine Aquarium magazine 17:(3)
- Dunz, A.R. & Schliewen, U.K. (2013): Molecular phylogeny and revised classification of the haplotilapiine cichlid fishes formerly referred to as "Tilapia". Molecular Phylogenetics and Evolution, Available online 29 March 2013 doi:10.1016/j.ympev.2013.03.015''
- De la Maza-Benignos, M., Ornelas-García, C. P., Lozano-Vilano, M.d.L., García-Ramírez, M.E. & Doadrio, I. (2015). "Phylogeographic analysis of genus Herichthys (Perciformes: Cichlidae), with descriptions of Nosferatu new genus and H. tepehua n. sp." (PDF). Hydrobiologia 748 (1): 201–231. doi:10.1007/s10750-014-1891-8.
- Barlow, G. W. (2000). The Cichlid fishes. Cambridge MA: Perseus Publishing.
- "Cichlidae". Integrated Taxonomic Information System.: National Museum of Natural History, Washington, D.C., 2004-05-11).
- Sany, R. H. (2012). Taxonomy of Cichlids and Angel. (Web publication).
|Wikimedia Commons has media related to Cichlidae.|
- Cichlid at DMOZ
- The Cichlid Fishes of Lake Malawi by Dr. Michael Oliver.
- Vision in Cichlids: Ecomorphology of vision in haplochromine cichlids of Lake Victoria by Dr. H.J. van der Meer.