''Amphilophus citrinellus'' is a large

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

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

endemic to the San Juan River and adjacent watersheds in

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

and

Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...

. In the

aquarium An aquarium (: aquariums or aquaria) is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. fishkeeping, Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aquati ...

trade ''A. citrinellus'' is often sold under the trade name of Midas cichlid. ''A. citrinellus'' are

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

and their diet consists of plant material,

molluscs Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

and smaller fish. The species is closely related to, but not to be mistaken for, ''

Amphilophus labiatus ''Amphilophus labiatus'' is a large cichlid fish endemic to Lake Managua and Lake Nicaragua in Central America. It is also known by the common name red devil cichlid, which it shares with another closely related cichlid, '' A. citrinellus''. Des ...

'', which shares the nickname red devil cichlid.

Physical characteristics

Midas cichlids are heavily built and are capable of standing up to any other aquarium-sized cichlid in fights over territory. They have powerful jaws, sharp teeth and a physical size advantage in comparison to other aquarium species. Therefore, the aggressivity of Midas cichlids should not be underestimated and cohabitants should be chosen carefully in an aquarium setting.

Taxonomic status

Considerable debate over the

taxonomic 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation ...

status of ''A. citrinellus'' began soon after the discovery of this species in the nineteenth century and continued throughout the twentieth century. A multivariate approach to treatment of anatomical characters has facilitated the discrimination among very similarly shaped species, aided by behavioral and ecological evidence. Multiple species of this group have been identified and verified by

genomic Genomics is an interdisciplinary field of molecular biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, ...

and

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

evidence in volcanic crater lakes Apoyo and Xiloá. The genetic evidence from Apoyo supports a hypothesis that the six known species of the lake evolved via

sympatric speciation Sympatric speciation is the evolution of a new species from a surviving Common descent, ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, ''sympatric'' and ''sympatry'' are ter ...

. A few to perhaps several dozen species fitting the

biological species concept A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of classification and ...

are considered to exist among what has historically been called ''A. citrinellus'', the great majority of which have not been described to date. The nine most recently described members of this species

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

are considered

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to their respective small, volcanic crater lakes. Colouration in wild stocks is variable, with most specimens grey to olive brown with a characteristic pattern of black dorsolateral bars, some pink, white, yellow or orange specimens do occur. These brightly colored forms, often called "golds", exist in nature at varying frequencies throughout the range of the species group. Colorations and morphological characters (e.g. accentuated nuchal humps) seen in the hobbyist trade are the product of selective breeding for several generations and may not be reflected in the wild.

Conservation status

The conservation status of only one species of this group has been analyzed. The arrow cichlid (''Amphilophus zaliosus'') was evaluated as Critically Endangered by the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

. Among the small body of information regarding populations of the species of this group, four other species may have smaller populations and/or ranges than this fish in Laguna de Apoyo: '' Amphilophus flaveolus'', '' Amphilophus chancho'', '' Amphilophus supercilius'', and '' Amphilophus globosus''. The final member of the complex, ''

Amphilophus astorquii ''Amphilophus'' is a genus of cichlid fishes from Central America, ranging from southern Mexico to Panama. The genus currently contains 23 species, including several that are well known from the aquarium trade. However, studies led by Oldřich ...

'', constitutes about eighty percent of the breeding population of Laguna de Apoyo.McCrary JK, Lopez Perez LJ (2008): El monitoreo de las mojarras (''Amphilophus'' spp.) en Nicaragua con aportes sobre su ecologia y estado de conservacion en la Laguna de Apoyo; Revista Nicaraguense BIODIVERSIDAD 1:43-5

/ref>

References

External links

Midas Cichlid

Mojarras de Apoyo a Museo Smithsonian" (in Spanish)

"Hallan Nuevas Mojarras" (in Spanish)

Midas Cichlids Care

* ttp://lagunadeapoyo.blogspot.com/2011/03/blog-post.html "Amphilophus astorquii in a multspecies school"
"Nesting ''Amphilophus globosus'' photographed"

* FishBase (2006) Eds. Froese, R. and D. Pauly. World Wide Web electronic publication
fishbase.org
version (07/2006). {{Taxonbar, from=Q206453 citrinellus Cichlid fish of Central America Fish of Costa Rica Freshwater fish of Nicaragua Fish of Lake Nicaragua Fish described in 1864 Taxa named by Albert Günther

Physical characteristics

Taxonomic status

Conservation status

See also

References

External links