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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: red swordtail

Synonyms and Other Names: green swordtail x southern platyfish (red swordtail x southern platyfish).

Identification: For information on hybridization between these species and their offspring see Gordon and Rosen (1951), Gordon and Gordon (1957), and Atz (1962). Distinguishing characteristics of the parent species were given by Rosen (1960, 1979) and Page and Burr (1991).

Size: Similar to parental species

Native Range: Not applicable.

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: Similar to parental species.

Means of Introduction: Most likely introduced through aquarium releases or fish farm escapes or releases.

Status: Unlikely to be established in Florida.  Shafland et al. (2008) do not list it as permanently established in the state.

Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.

Remarks: In captivity, these two species are often crossbred to produce a wide variety of hybrid offspring, many of which are fertile (Dawes 1991), for the aquarium marketplace. Although easily hybridized experimentally, natural hybrids are unknown (Rosen 1960). A population found in Indian Spring, Clark County, Nevada, was originally reported to be this hybrid (Courtenay and Deacon 1982; Deacon and Williams 1984; Page and Burr 1991); however, in 1989 Rauchenberger (personal communication) examined the Nevada voucher specimens (UF 91919) and concluded that all were X. hellerii.

One voucher specimen exists for the 1978 Hillsborough County, Florida record (UF 171711).

References: (click for full references)

Atz, J.W. 1962. Effects of hybridization on pigmentation in fishes of the genus Xiphophorus. Zoologica 47:153-181.

Courtenay, W.R., Jr., and J.E. Deacon. 1982. Status of introduced fishes in certain spring systems in southern Nevada. Great Basin Naturalist 42(3):361-366.

Courtenay, W.R., Jr., H.F. Sahlman, W.W. Miley, II, and D.J. Herrema. 1974. Exotic fishes in fresh and brackish waters of Florida. Biological Conservation 6(4):292-302.

Deacon, J.E., and J.E. Williams. 1984. Annotated list of the fishes of Nevada. Proceedings of the Biological Society of Washington 97(1):103-118.

Gordon, H., and M. Gordon. 1957. Maintenance of polymorphism by potentially injurious genes in eight natural populations of the platyfish, Xiphophorus maculatus. Journal of Genetics 55(1):1-44.

Gordon, M., and D.E. Rosen. 1951. Genetics of species differences in the morphology of the male genitaliaof xiphophorin fishes. Bulletin of the American Museum of Natural History 95(7):415-464.

Page, L.M., and B.M. Burr. 1991. A field guide to freshwater fishes of North America north of Mexico. The Peterson Field Guide Series, volume 42. Houghton Mifflin Company, Boston, MA.

Rosen, D.E. 1960. Middle-American poeciliid fishes of the genus Xiphophorus. Bulletin of the Florida State Museum Biological Sciences 5(4):57-242.

Rosen, D.E. 1979. Fishes from the uplands and intermontane basins of Guatemala: revisionary studies and comparative geography. Bulletin of the American Museum of Natural History 162:267-376.

Shafland, P.L., K.B. Gestring, and M.S. Stanford. 2008. Florida's Exotic Freshwater Fishes - 2007. Florida Scientist 71(3):220-245.

Other Resources:
Fact Sheet for Xiphophorus hellerii - USGS Nonindigenous Aquatic Species Database

Fact Sheet for Xiphophorus maculatus - USGS Nonindigenous Aquatic Species Database

Author: Leo Nico,Pam Fuller, and Bill Loftus

Peer Review Date: 9/17/2012

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.