Cichlids /ˈsɪklɪdz/ are fish from the family Cichlidae in the order Cichliformes. Cichlids were traditionally classed in a suborder, Labroidei, along with the wrasses (Labridae), in the order Perciformes but molecular studies have contradicted this grouping. The closest living relatives of cichlids are probably the convict blennies and both families are classified in the 5th edition of Fishes of the World as the two families in the Cichliformes, part of the subseries Ovalentaria. 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.
Many cichlids, particularly tilapia, are important food fishes, while others, such as the Cichla species, are valued game fish. The family also includes many popular freshwater aquarium fish kept by hobbyists, 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.
All cichlids have some form of parental care for their eggs and fry. That parental care may come in the form of guarding the eggs and fry or it may come in the form of mouthbrooding.
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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 (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.
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.
The features that distinguish them from the other families in Labroidei include:
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.
In cichlid taxonomy, dentition was formerly used as a classifying characteristic. However, this was complicated by the fact that in many cichlids, tooth shape changes with age, due to wear, and cannot be relied upon. Genome sequencing and other technologies transformed cichlid taxonomy.
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.), two in Iran (Iranocichla), and three in India and Sri Lanka (Etroplus and Pseudetroplus). 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. The deepest known occurrence are Trematocara at more than 300 m (980 ft) below the surface in Lake Tanganyika. Others found in relatively deep waters 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.
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.
Aggressive behavior in cichlids is ritualized and consists of multiple displays used to seek confrontation while being involved in evaluation of competitors, coinciding with temporal proximity to mating. Displays of ritualized aggression in cichlids include a remarkably rapid change in coloration, during which a successfully dominant territorial male assumes a more vivid and brighter coloration while a subordinate or “non-territorial” male assumes a dull-pale coloration. In addition to color displays, cichlids employ their lateral lines to sense movements of water around their opponents to evaluate the competing male for physical traits/fitness. Male cichlids are very territorial due to the pressure of reproduction, males establish their territory and social status by physically driving out challenging males (novel intruders) through lateral displays (parallel orientation, uncovering gills), biting, or mouth fights (head-on collisions of ajar mouths, measuring jaw sizes, and biting each other's jaws). The cichlid social dichotomy is composed of a single dominant with multiple subordinates, where the physical aggression of males become a contest for resources (mates, territory, food). Female cichlids prefer to mate with a successfully alpha male with vivid coloration, whose territory has food readily available.
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 all include – or consist entirely of – monogamous mouthbrooders. In contrast, numerous open- or cave-spawning cichlids are polygamous; examples include many Apistogramma, Lamprologus, Nannacara, and Pelvicachromis species.
Most adult male cichlids, specifically in the Haplochromini tribe of cichlids, exhibit a unique pattern of oval-shaped, color dots on their anal fins. These phenomena are known as egg-spots and aid in the mouthbrooding mechanisms of cichlids. The egg-spots consist of carotenoid based pigment cells, which indicates a high cost to the organism, when considering that fish are not able to synthesize their own carotenoids.
The mimicry of egg-spots is utilized by males for the fertilization process. Mouthbrooding females lay eggs and immediately snatch them up with their mouths. Over millions of years, male cichlids have evolved egg-spots to initiate the fertilization process more efficiently. When the females are snatching up the eggs into their mouth, the males gyrate their anal fins, which illuminates the egg-spots on his tail. Afterwards, the female, believing these are her eggs, places her mouth to the anal fin (specifically the genital papilla) of the male, which is when he discharges sperm into her mouth and fertilizes the eggs.
The genuine color of egg spots is a yellow, red or orange inner circle with a colorless ring surrounding the shape. Through phylogenetic analysis, using the mitochondrial ND2 gene, it was hypothesized that the true egg spots evolved in the common ancestor of the Astatoreochromis-lineage and the modern Haplochrominis. This ancestor was most likely riverine in origin, based upon the most parsimonious representation of habitat type in the cichlid family. The presence of egg-spots in a turbid riverine environment, would seem particularly beneficial and necessary for intra-species communication.
There are two pigmentation genes that are found to be associated with egg-spot patterning and color arrangement. These are fhl2-a and fhl2-b, which are paralogs. These genes aid in pattern formation and cell-fate determination in early embryonic development. The highest expression of these genes was temporally correlated with egg-spot formation. A SINE (short interspersed repetitive element) was also seen to be associated with egg-spots. Specifically, it was evident upstream of the transcriptional start site of fhl2 in only haplochrominis species with egg-spots 
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 (such as Sarotherodon melanotheron), Chromidotilapia guentheri, and some Aequidens species. This method appears to have evolved independently in several groups of African cichlids.
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. Such a process can happen through allopatric speciation, whereby species diverge according to different selection pressures in different geographical areas, or through sympatric speciation, by which new species evolve from a common ancestor while remaining in the same area. In Lake Apoyo in Nicaragua, Amphilophus zaliosus and its sister species Amphilophus citrinellus display many of the criteria needed for sympatric speciation. In the African rift lake system, cichlid species in numerous distinct lakes evolved from a shared hybrid swarm.
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), Nile tilapia (Oreochromis niloticus), and water hyacinth, deforestation that led to water siltation, and overfishing, many Lake Victoria cichlid species have become extinct or been drastically reduced. By around 1980, lake fisheries yielded only 1% cichlids, a drastic decline from 80% in earlier years.
By far the largest Lake Victoria group are the haplochromine cichlids, with more than 500 species, but at least 200 of these (approximately 40%) have become extinct, and many others are seriously threatened. Initially it was feared that the percentage of extinct species was even higher, but some species have been rediscovered after the Nile perch started to decline in the 1990s. Some species have survived in nearby small satellite lakes, or in refugia among rocks or papyrus sedges (protecting them from the Nile perch), or have adapted to the human-induced changes in the lake itself. The species were often specialists and these were not affected to the same extent. For example, the piscivorous haplochromines were particularly hard hit with a high number of extinctions, while the zooplanktivorous haplochromines reached densities in 2001 that were similar to before the drastic decline, although consisting of fewer species and with some changes in their ecology.
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. 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).
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.
Adrianus Franciscus Johannes Marinus Maria "Ad" Konings (born 11 January 1956 in Roosendaal, Netherlands) is an ichthyologist originally trained in medicine and biology. Konings is best known for his research on African rift lake cichlids. After studies in Amsterdam, he has spent most of his life in Rotterdam.Adaptive radiation
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos ("Darwin's finches"), but examples are known from around the world.Blood parrot cichlid
The blood parrot cichlid (or more commonly and formally known as parrot cichlid; no binomial nomenclature) is a hybrid thought to be between the midas and the redhead cichlid, although the true parent species has not confirmed by breeders. The fish was first created in Taiwan around 1986. Blood parrots should not be confused with other parrot cichlids or salt water parrotfish (family Scaridae).Because this hybrid cichlid has various anatomical deformities, controversy exists over the ethics of creating the blood parrot. One deformity is its mouth, which has only a narrow vertical opening. This makes blood parrots somewhat harder to feed and potentially vulnerable to malnutrition.Cichlinae
The Cichlinae are a subfamily of fishes in the cichlid family, native to South America.
This subfamily consists of approximately 117 described species as of July 2017. Some authors have suggested that the Cichlinae encompasses all of the Neotropical Cichlids and found the taxon to be monphyletic and to be divided into seven tribes: Astronotini, Chaetobranchini, Cichlasomatini, Cichlini, Geophagini, Heroini, and Retroculini. In this system the Geophaginae plus the Chaetobranchini were recovered as the sister taxon to the clade consisting of the Heroini plus the Cichlatsomatini, these latter two being referred to as the subfamily Cichlasomatinae in some classifications, while the monogeneric Astronotini was a sister taxon to these four, while the Cichlini and Retroculini made up a sister clade of the other five.Convict cichlid
The convict cichlid (Amatitlania nigrofasciata) is a fish species from the family Cichlidae, native to Central America, also known as the zebra cichlid. Convict cichlids are popular aquarium fish and have also been the subject of numerous studies on fish behaviour.The convict cichlid is a rather small cichlid species. Males grow to be around 6.5 inches (17 cm) long and females closer to 4.5 inches (11 cm) long, with both genders weighing around 35 grams (1.2 oz). It comes in a wide variety of colors, with females being more highly colored. Young usually take around 6 months to mature, during which time both parents care for their young and carry out several parenting tasks. Convict chichlids are known to be highly aggressive when breeding, and tend to be more aggressive at higher temperatures.Geophagini
Geophagus is a tribe of cichlids from the subfamily Cichlinae, the American cichlids. It is the sister taxon to the clade which includes the Cichlasomatini and Heroini. Fishes in the Geophagini are distributed from Panama south to Argentina, it is the most speciose of the seven tribes within the Cichlinae and it is subdivided into three sub-tribes, Acarichthyina, Crenicaratina, and Geophagina which together contain over 200 species. Geophagines show morphological and behavioural specialisations to enable them to sift the substrates within their mouths so that they can separate benthic invertebrates from substrates dominated by sand or silt.Green chromide
The green chromide (Etroplus suratensis) is a species of cichlid fish from freshwater and brackish water in southern India and Sri Lanka. Other common names include pearlspot cichlid, banded pearlspot, and striped chromide. In Kerala in India it is known locally as the karimeen. In Goa the fish is known as Kalundar
In Sri Lanka this fish is known as Koraliya
This fish is native to Sri Lanka and coastal regions of India. Many populations are likely introductions. It is also introduced in Singapore, where it occurs in estuaries.The adult is oval in shape with a short snout. It is gray-green in colour with dark barring and a dark spot at the base of the pectoral fin. It commonly reaches 20 centimetres (7.9 in) in length, and the maximum length is twice that.This species lives in brackish water habitat types, such as river deltas. It eats mainly aquatic plants, but it consumes the occasional mollusk, diatoms, and other animal matter. This species engages in attentive parental care in which several adults care for each brood.In Sri Lanka vocal name for this fish is Koraliya (කොරළියා). In 2010 this species was named the official state fish of Kerala. The following year was declared "The Year of the Karimeen". Karimeen pollichadhu, a fried dish, is a delicacy served in restaurants. It is familiar to tourists, but because it is very expensive it is not easily accessible to the common man. Production of the species for food is expected to increase in the near future.They are closely related to the Paretroplus fishes from Madagascar.Etroplus suratensis and E. maculatus form the main species and the former is dominant among Pearl spots in reservoirs of India. They mainly feed
on detritus and occupy the same niche as that of Oreochromis mossambicus. These fishes are very popular food fishes but their biomass is very low in reservoirs compared to other cichlids.Haplochromine
The haplochromine cichlids are a tribe of cichlids in subfamily Pseudocrenilabrinae called Haplochromini. This group includes the type genus (Haplochromis) plus a number of closely related genera such as Aulonocara, Astatotilapia, and Chilotilapia. They are endemic to eastern, southern and northern Africa, except for Astatotilapia flaviijosephi in the Middle East. A common name in a scientific context is East African cichlids – while they are not restricted to that region, they are the dominant Cichlidae there. This tribe was extensively studied by Ethelwynn Trewavas, who made major reviews in 1935 and 1989, at the beginning and at the end of her career in ichthyology. Even today, numerous new species are being described each year.
The haplochromines were in older times treated as subfamily Haplochrominae, However, the great African radiation of pseudocrenilabrine cichlids is certainly not monophyletic without them, and thus they are today ranked as a tribe therein. They do include, however, the type genus of the subfamily, Pseudocrenilabrus. Since taxonomic tribes are treated like genera for purposes of biological nomenclature according to the ICZN, the Haplochromis is the type genus of this tribe, and not the (later-described) Pseudocrenilabrus, even though the tribe name Pseudocrenilabrini was proposed earlier.
In the African Great Lakes, there has been an amazing adaptive radiation of Haplochromini. Many have interesting behavior (e.g. mouthbrooding in Astatotilapia burtoni or the "sleeper" ambushes of Nimbochromis), and brilliant colours are also widespread. Males and females are often strikingly sexually dichromatic. In the aquarium hobby, these fishes are popular for these reasons. They are often aggressive and demand rather unusual water parameters, making them generally unsuited for beginners or community tanks. There are some informal names used among aquarists for Haplochromini. Generally, any and all (as well as some similar-looking Pseudocrenilabrinae) may be referred to haplos, haps or happies. More specific terms are mbuna ("rock-dwelling browser") and utaka ("free-roaming hunter"), which are Bantu terms for these two ecological groups.
Haplochromines inhabit both rivers and lakes, but it is the lake species that have been most closely studied because of the species flocks known from some of the larger lakes, such as Lake Malawi. In the aquarium hobby, the "happies" are conveniently divided into four groups:
Riverine species and those endemic to the northern Great Lakes such as Lake Kivu and Lake Victoria
Mbuna, endemic to Lake Malawi
Utaka and other non-mbuna species endemic to Lake Malawi
Species endemic to Lake TanganyikaLake Victoria's trophic web was thoroughly upset in the second half of the 20th century, after Nile Perch (Lates niloticus) were introduced to the lake. Among the haplochromines found there, there have been many extinctions, and a number of other species only survive in aquaria. One monotypic genus, Hoplotilapia, is believed to be entirely extinct at least in the wild.Heroini
Heroini is a fish tribe from the Cichlasomatinae subfamily in the cichlid family. All cichlids native to the Greater Antilles, United States (southern Texas), Mexico and northern Central America are members of this tribe. It also includes most cichlid species in southern Central America (where only non-Heroini cichlids are Andinoacara and Geophagus) and several species from South America (where several other tribes exist). A large percentage of its species were formerly placed in the genus Cichlasoma (itself now placed in the tribe Cichlasomatini), but have since been moved to other genera.
In other classifications the tribe Heroini is placed in the subfamily Cichlinae.Lake Tanganyika
Lake Tanganyika is an African Great Lake. It is the second oldest freshwater lake in the world, the second largest by volume, and the second deepest, in all cases after Lake Baikal in Siberia. It is the world's longest freshwater lake. The lake is divided among four countries – Tanzania, Democratic Republic of the Congo (DRC), Burundi, and Zambia, with Tanzania (46%) and DRC (40%) possessing the majority of the lake. The water flows into the Congo River system and ultimately into the Atlantic Ocean.List of freshwater aquarium fish species
A vast number of aquatic species have successfully adapted to live in the freshwater aquarium. This list gives some examples of the most common species found in home aquariums.Oscar (fish)
The oscar (Astronotus ocellatus) is a species of fish from the cichlid family known under a variety of common names, including tiger oscar, velvet cichlid, and marble cichlid. In tropical South America, where the species naturally resides, A. ocellatus specimens are often found for sale as a food fish in the local markets. The fish has been introduced to other areas, including China, Australia, and the United States. It is considered a popular aquarium fish in Europe and the U.S.Paedophagy
Paedophagy (literally meaning the "consumption of children") in its general form is the feeding behaviour of fish or other animals whose diet is partially, or primarily the eggs or larvae of other animals. However, P. H. Greenwood, who was the first to describe paedophagia, defines it to be a feeding behaviour evolved among cichlid fishes.Parachromis managuensis
Parachromis managuensis is a large species of cichlid native to freshwater habitats in Central America, where found from Honduras to Costa Rica. The scientific name refers to Lake Managua in Nicaragua from where the holotype was obtained. It is a food fish and is also found in the aquarium trade where it is variously known as the jaguar cichlid, managuense cichlid, managua cichlid, guapote tigre, Aztec cichlid, spotted guapote and jaguar guapote. Males grow to a total length of 35 centimetres (14 in) and females to 30 centimetres (12 in).The species is a carnivorous, highly predatory fish. Their diet consists mainly of small fish and macroinvertebrates. They prefer turbid, eutrophic lakes, often found in warm water depleted of oxygen. Their native substrate is one of mud-bottoms, but can also be found in other ponds and springs with sandy bottoms covered in plant debris. They inhabit lakes in a tropical climate and prefer water with a 7.0–8.7 pH, a water hardness of 10–15 dGH, and a temperature range of 25 to 36 °C (77 to 97 °F). They are usually found at depths of from 3 to 10 metres (10 to 33 ft).Pharyngeal jaw
Pharyngeal jaws are a "second set" of jaws contained within an animal's throat, or pharynx, distinct from the primary or oral jaws. They are believed to have originated as modified gill arches, in much the same way as oral jaws.
Most fish species with pharyngeal teeth do not have extendable pharyngeal jaws. A particularly notable exception is the highly mobile pharyngeal jaw of the moray eels. These are possibly a response to their inability to swallow as other fishes do by creating a negative pressure in the mouth, perhaps induced by their restricted environmental niche (burrows). Instead, when the moray bites prey, it first bites normally with its oral jaws, capturing the prey. Immediately thereafter, the pharyngeal jaws are brought forward and bite down on the prey to grip it; they then retract, pulling the prey down the moray eel's gullet, allowing it to be swallowed.Another notable example are fish from the family Cichlidae. Cichlid pharyngeal jaws have become very specialized in prey processing and may have helped cichlid fishes become one of the most diverse families of vertebrates. However, later studies based on Lake Victoria cichlids suggest that this trait may also become a handicap when competing with other predator species.Pseudocrenilabrinae
The Pseudocrenilabrinae are a subfamily in the cichlid family of fishes to which, according to a study from 2004, includes all the Middle Eastern and African cichlids with the exception of the unusual Heterochromis multidens and the Malagasy species. This subfamily includes more than 1,100 species. Previous authors recognized additional African subfamilies, e.g. the Tilapiinae of Hoedeman (1947), Tylochrominae of Poll (1986), or Boulengerochrominae of Tawil (2001).
To this subfamily belong the cichlids from the African Great Lakes, such as the utaka and mbuna in Lake Malawi, and various species from Lake Victoria and Lake Tanganyika.
The Pseudocrenilabrinae tribes Haplochromini and Oreochromini are widespread in Africa and also found in the Middle East, while Chromidotilapiini, Hemichromini and Tylochromini are primarily West and Central African. The remaining tribes are largely or entirely restricted to Lake Tanganyika.Ram cichlid
The ram cichlid, Mikrogeophagus ramirezi, is a species of freshwater fish endemic to the Orinoco River basin, in the savannahs of Venezuela and Colombia in South America. The species has been examined in studies on fish behaviour and is a popular aquarium fish, traded under a variety of common names, including ram, blue ram, German blue ram, Asian ram, butterfly cichlid, Ramirez's dwarf cichlid, dwarf butterfly cichlid and Ramirezi. The species is a member of the family Cichlidae and subfamily Geophaginae.Tilapia
Tilapia ( tih-LAH-pee-ə) is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia are mainly freshwater fish inhabiting shallow streams, ponds, rivers, and lakes, and less commonly found living in brackish water. Historically, they have been of major importance in artisanal fishing in Africa, and they are of increasing importance in aquaculture and aquaponics. Tilapia can become a problematic invasive species in new warm-water habitats such as Australia, whether deliberately or accidentally introduced, but generally not in temperate climates due to their inability to survive in cold water.
Tilapia is the fourth-most consumed fish in the United States dating back to 2002. The popularity of tilapia came about due to its low price, easy preparation, and mild taste.Tilapiine cichlid
The Tilapiini are a tribe within the family Cichlidae commonly known as tilapiine cichlids. Most of the taxa herein are called "tilapias", formerly this was considered to be a more diverse grouping which contained the economically important genera Oreochromis, Sarotherodon, and Tilapia. A number of smaller genera, such as Alcolapia, Danakilia, Iranocichla, and Steatocranus were also placed herein. The Tilapiini are now placed in the subfamily Pseudocrenilabrinae of African and Middle Eastern cichlids; formerly, these were often regarded as a distinct subfamily Tilapiinae.