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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: black tetra

Synonyms and Other Names: Tetragonopterus ternetzi Boulenger, 1895

Taxonomy: available through www.itis.gov

Identification: Géry (1977) provided an identification key and color photographs. Color photographs were also provided in Axelrod et al. (1985) and Sakurai et al. (1993).

Size: 5-7.5 cm SL

Native Range: Tropical America. Amazon (Guaporé drainage) and La Plata (Paraguay River) basins in southern Brazil, Argentina, and Bolivia, South America (Géry 1977).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: The Colorado introduction resulted from an escape from a local tropical fish farm, and the Florida record may represent either an aquarium release or a fish farm escape. The Louisiana collection took place near a tropical fish farm and was likely and escapee.

Status: Failed in Colorado, Florida, 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 a well-known species among aquarists. The hot springs area of Colorado where this fish was found is at an altitude of 8,000 ft and has very cold winters, but L. Zuckerman (personal communication) suggested that some introduced species might spread downstream during warmer months and reach other thermal refugia.

Voucher specimens: Florida (UF 87974, 97058). The Colorado specimens were reportedly deposited with the U.S. Fish and Wildlife Service, Fort Collins (Zuckerman, personal communication). Zuckerman's Colorado collections were later transferred to the University of New Mexico, Albuquerque; however, Gymnocorymbus did not appear in a 1995 list of deposited fishes provided by the collections manager.

References: (click for full references)

Axelrod, H.R., W.E. Burgess, N. Pronek, and J.G. Walls. 1985. Dr. Axelrod's atlas of freshwater aquarium fishes. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Courtenay, W.R., Jr., and D.A. Hensley. 1979. Survey of introduced non-native fishes. Phase I Report. Introduced exotic fishes in North America: status 1979. Report Submitted to National Fishery Research Laboratory, U.S. Fish and Wildlife Service, Gainesville, FL.

Géry, J. 1977. Characoids of the world. Tropical Fish Hobbyist Publications, Inc., Neptune City, NJ.

Piller, K. - Southeastern Louisiana University.

Zuckerman, L. - Aquatic Ecologist, Kansas Department of Wildlife and Parks, Pratt, KS.

Zuckerman, L.D., and R.J. Behnke. 1986. Introduced fishes in the San Luis Valley, Colorado. Pages 435-452 in R.H. Stroud, ed. Fish culture in fisheries management. Proceedings of a symposium on the role of fish culture in fisheries management at Lake Ozark, MO, March 31-April 3, 1985. American Fisheries Society, Bethesda, MD.

Other Resources:
US Fish and Wildlife Service Ecological Risk Screening Summary for Gymnocorymbus ternetzi

Author: Leo Nico, and Pam Fuller

Peer Review Date: 1/31/2005

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.