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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: Mexican Tetra

Taxonomy: available through www.itis.gov

Identification: Although previously considered a subspecies of Astyanax fasciatus (Lee et al. 1980 et seq.), A. mexicanus more likely represents a species complex (Mayden et al. 1992). Sublette et al. (1990) and Page and Burr (1991) gave distinguishing characteristics. The species was included in a state key by Miller (1952). Illustrations and photographs were provided by Miller (1952), Miller and Robison (1973), Minckley (1973), Sublette et al. (1990), and Page and Burr (1991).

Size: 12 cm.

Native Range: Subtropical America. Mostly eastern and central Mexico and also the lower Rio Grande, lower Pecos, and Nueces rivers in Texas (Lee et al. 1980 et seq.; Page and Burr 1991). Historically, found in the Pecos River drainage and lower Rio Grande in New Mexico, but now restricted to the Pecos drainage downstream of Dexter (Sublette et al. 1990).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Native range data for this species provided in part by NatureServe

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

Means of Introduction: All or most introductions have probably resulted from bait bucket releases (e.g., Miller and Robison 1973). The first A. mexicanus observed outside their native range were seen in a bait shop in Yuma, Arizona, along the Colorado River in 1950; presumably, these fish were a species contaminant that arrived in a minnow shipment (Evans and Douglas 1950; Miller 1952).

Status: Established in Texas (outside native range). Formerly found in the Rio Grande valley in New Mexico, but now possibly extirpated (although these likely represented native records and not introductions). Previously established in southern Oklahoma; the species has not been taken in recent years and is now considered extirpated (Cashner and Matthews 1988). Reported from Arizona, California, and Louisiana.

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: This is the only characid species native to the United States. Because it is predacious and highly aggressive, there is concern that this species could impact native fishes by preying on their young (Miller 1952; Minckley 1973). Lee et al. (1980 et seq.) and Page and Burr (1991) provided distribution maps; these authors considered Mexican tetra populations recorded from the Rio Grande drainage in southern New Mexico, and in the associated nearby border area of Texas, to be introduced. In contrast, Sublette et al. (1990) believed that this area constituted part of the species' natural or historical distribution. It now appears to be extirpated from the Rio Grande in New Mexico and is on the decline in many portions of the Pecos River drainage; as such, the species is classified as "state endangered" by New Mexico (Sublette et al. 1990).

Voucher specimens: Ohio (OSM 14147); Texas (INHS 75684).

References: (click for full references)

Bechler, D. L., and R. C. Harrel. 1994. Notes on the biology and occurrence of Astyanax mexicanus (Characidae, Teleostei) in southeast Texas. Texas Journal of Science 46(3):293-294.

Cashner, R. C., and W. J. Matthew. 1988. Changes in the known Oklahoma fish fauna from 1973 to 1988. Proceedings of the Oklahoma Academy of Science 68:1-7.

Conner, J. V., and R. D. Suttkus. 1986. Zoogeography of freshwater fishes of the western Gulf Slope of North America. Pages 413-456 in C. H. Hocutt and E. O. Wiley, editors. The zoogeography of North American freshwater fishes. John Wiley and Sons, New York, NY.

Dowell, V. E., and C. D. Riggs. 1958. Further observation on Astyanax fasciatus and Menidia audens in Lake Texoma. Proceedings of the Oklahoma Academy of Science 33(1955):52-53.

Evans, W. A., and P. A. Douglas. 1950. Notes on fishes recently introduced into southern California. California Fish and Game 36:435-436.

Hubbs, C., T. Lucier, G. P. Garrett, R. J. Edwards, S. M. Dean, E. Marsh, and D. Belk. 1978. Survival and abundance of introduced fishes near San Antonio, Texas. Texas Journal of Science 30(4):369-376.

Hubbs, C. L., W. I. Follett, and L. J. Dempster. 1979. List of the fishes of California. California Academy Science Occasional Papers 133. 51 pp.

Koster, W. J. 1957. Guide to the fishes of New Mexico. University of New Mexico Press, Albuquerque, NM.

Lambou, V. W. 1962. Fishes occurring in Lake Bistineau, Louisiana. Proceedings of the Louisiana Academy of Sciences 25:75-79.

Lee, D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer, Jr. 1980 et seq. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, NC.

Mayden, R. L., editor. 1992. Systematics, historical ecology, and North American freshwater fishes. Stanford University Press, Stanford, CA.

Miller, R. J., and H. W. Robison. 1973. The fishes of Oklahoma. Oklahoma State University Press, Stillwater, OK.

Miller, R. R. 1952. Bait fishes of the lower Colorado River, from Lake Mead, Nevada, to Yuma, Arizona, with a key for identification. California Fish and Game 38(1):7-42.

Minckley, W. L. 1973. Fishes of Arizona. Arizona Fish and Game Department. Sims Printing Company, Inc., Phoenix, AZ.

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.

Riggs, C. D. 1954. The occurrence of Astyanax fasciatus mexicanus in Lake Texoma, Oklahoma. Proceedings of the Oklahoma Academy of Science 33(1952):141.

Sublette, J. E., M. D. Hatch, and M. Sublette. 1990. The fishes of New Mexico. New Mexico Department of Game and Fish, University of New Mexico Press, Albuquerque, NM. 393 pp.

Swift, C. C., T. R. Haglund, M. Ruiz, and R. N. Fisher. 1993. The status and distribution of the freshwater fishes of southern California. Bulletin of the Southern California Academy of Science 92(3):101-167.

Trautman, M. B. 1981. The fishes of Ohio. Ohio State University Press, Columbus, OH.

Other Resources:

Author: Nico, L.

Peer Review Date: 7/27/2004

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.