The southern platyfish, common platy, or moonfish (''Xiphophorus maculatus'') is a

species 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 Taxonomy (biology), ...

freshwater fish Freshwater fish are fish species that spend some or all of their lives in bodies of fresh water such as rivers, lakes, ponds and inland wetlands, where the salinity is less than 1.05%. These environments differ from marine habitats in many wa ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Poeciliidae Poeciliidae are a Family (biology), family of freshwater ray-finned fishes of the order Cyprinodontiformes, the tooth-carps, and include well-known live-bearing aquarium fish, such as the guppy, Poecilia, molly, Platy (fish), platy, and Green swo ...

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Cyprinodontiformes Cyprinodontiformes is an order (biology), order of Actinopterygii, ray-finned fish, comprising mostly small, freshwater fish. Many popular aquarium fish, such as killifish and Poeciliidae, live-bearers, are included. They are closely related t ...

. A live-bearer, it is closely related to the

green swordtail The green swordtail (''Xiphophorus hellerii'') is a species of freshwater/brackish fish in family Poeciliidae of order Cyprinodontiformes. A live-bearer, it is closely related to the southern platyfish or 'platy' (''X. maculatus'') and can ...

(''X. hellerii'') and can interbreed with it. It is native to an area of North and Central America stretching from

Veracruz Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entit ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, to northern

Belize Belize is a country on the north-eastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a maritime boundary with Honduras to the southeast. P ...

. The southern platyfish grows to a maximum overall length of .

Sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

is slight, the male's

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

being more pointed. The

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

of the male fish has evolved into a

gonopodium Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

, a stick-shaped organ used for

reproduction Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: Asexual reproduction, asexual and Sexual ...

. The female southern platyfish's anal fin is fan shaped. Wild varieties are drab in coloration, lacking the distinctive dark lateral line common to many ''Xiphophorus'' species. ''X. maculatus'' prefers slow-moving waters of canals, ditches, and warm springs.

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 ...

, its diet includes both plants and small

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s, and

annelid The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to vario ...

worms. Breeders have developed a multitude of color varieties (e.g. orange, red, yellow, red/black, and black/white) which are common

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 ...

fish for hobbyists. The southern platyfish is commonly known simply as the platy (pl. platys or platies), from the fish's original generic name, ''Platypoecilus''.

Nonindigenous occurrences

This species has been recorded from Orange County, California, near Westminster; near a fish farm in Conejos County and the

South Platte The South Platte River is one of the two principal tributaries of the Platte River. Flowing through the U.S. states of Colorado and Nebraska, it is itself a major river of the American Midwest and the American Southwest/ Mountain West. I ...

drainage, Colorado; several counties in

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

;

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

; an unnamed tributary to Big Branch Bayou in Lacombe, Louisiana; Beaverhead Rock Pond (Madison County), Montana; Clark County, Nevada; and Texas. It has also been collected in the Loiza drainage near Loiza Reservoir, Quebrada Honda, and Rio Abajo Forest Station north of Utuado in Puerto Rico. The southern platyfish has been released probably due to fish farm or aquarium releases. Specimens in Louisiana were collected near a tropical fish farm. Southern platies, and other introduced poeciliids, have been implicated in the decline of native damselflies on Oahu, Hawaii. Often the distributions of the damselflies and introduced fishes were found to be mutually exclusive, probably resulting from competition for limited insect food.

In the aquarium

Platies are easy to keep and well suited to a community aquarium. They prefer water with a 7.0–8.0 pH, a water hardness of 9.0–19.0 dGH, and a temperature range of . In captivity, they reach maturity in three to four months, and breed readily, the females giving birth to about 20–40 young at a time. Often young are eaten by the adults or other inhabitants of a communal aquarium but given plants and gravel to hide in, some will probably survive as these are hardy fish. Platy young are first seen at approx 7mm long and will use cover to hide from predators and to look for food. Specialist fry food is available but any flake food, frozen or live food that floats their way will be easily consumed. These require excellent water quality and care must be taken to avoid fry being sucked up into a gravel cleaning syphon. A thin membrane covering the syphon opening such as a clean pair of tights will minimise this. The fish commonly sold in pet shops is not a pure strain of ''X. maculatus'', but is a hybrid between ''X. hellerii'' and ''X. maculatus''. In general, if the male has a sword-shaped tail, they are called swordtails. Otherwise, they are labeled platy. (However, this basic assessment does not take into consideration the undeniable fact that the majority of fishes sold as 'platies' do share the same stout form as the wild ''X. maculatus'', whilst aquarium 'hybrid' swordtail strains likewise share the longer, larger body-form of the wild ''X. hellerii'', so caudal extension is not the sole differentiator and it is clear that decades of selective breeding have reinforced, within each captive strain, the appropriate or typical – and therefore desired – body shape of the name types.) Color and fin shape vary wildly in the aquarium trade. A common statement in the trade is that it is harder to stop them breeding than to make them do so, with ‘surprise’ fry appearing in community tanks regularly.

Genetics

The

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

of ''Xiphophorus maculatus'' was sequenced in 2013.

Sex

The southern platyfish has three sex chromosomes W, X, and Y, that interact with autosomal genes. This creates a highly complex sex determination system. * The Y chromosome carries a dominant male-determining gene (''M''), which is thought to be homologous to the mammalian ''SRY'' gene located on the Y chromosome. * The W chromosome carries a suppressor gene (''S'') that inhibits the activity of the male-determining gene (''M'') on the Y chromosome. This explains why WY individuals develop as females. * The X chromosome lacks the suppressor gene (''S'') found on the W chromosome, allowing XY and YY individuals to develop as males. There are 4 autosomal alleles that intervene in the sex determination system: * A recessive autosomal factor ''a'', can, in its homozygous state (''aa''), activate the male-determining gene on the X chromosome. This leads to the development of XX males. * Two recessive alleles ''b'' and ''c'', likely acting in concert, can activate the male-determining gene located on the W chromosome. This activation can result in WW, WX, and even WY individuals developing as males. The ''b'' factor appears to specifically suppress the W-linked suppressor (''S''). * The dominant ''T'' allele interacts with a specific variant of the Y chromosome (designated as Y') to promote female development in some XY individuals.

Gallery

File:Xiphophorus maculatus young.jpg, Fry File:Pregnant x. maculatus.jpg, Pregnant female File:PlatyGonopodium.jpg, Male platy with gonopodium File:Twin Bar Platy Female.jpg, Female ‘Twin Bar’ or ‘Comet’ platy File:Platy 009.jpg, ‘Sunset’ platy File:Poissons 06.jpg, Wagtail platy File:Platy blu.jpg, Blue platy File:18 marca 06 r. 015.jpg, ‘Hi-fin’ wagtail File:Xiphophorus_maculatus.jpg, Red ‘Salt and Pepper’ platy File:Black Platy.jpg, Female black platy

References

External links

* *
Southern Platyfish

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

factsheet *View th
platyfish genome
in

Ensembl Ensembl genome database project is a scientific project at the European Bioinformatics Institute, which provides a centralized resource for geneticists, molecular biologists and other researchers studying the genomes of our own species and other v ...

{{DEFAULTSORT:platyfish, southern southern platyfish Live-bearing fish Ovoviviparous fish Fish of Belize Fish of Guatemala Freshwater fish of Mexico southern platyfish southern platyfish Freshwater fish of the United States