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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: head-and-taillight tetra

Taxonomy: available through www.itis.gov

Identification: The genus Hemigrammus needs systematic revision. See Géry (1977) for identification key and photographs. Color photographs were also provided in Axelrod et al. (1985) and Sakurai et al. (1993).

Size: 4 cm.

Native Range: Tropical America. The true Hemigrammus ocellifer is native to drainages in northeastern South America, including French Guiana, Guyana, and Venezuela (Géry 1977). Closely related members of the genus occur from Venezuela to Argentina (Géry 1977).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: Records represent escapes from areas of the hot springs used for culturing ornamental fish.

Status: Reported from Colorado.

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: The hot springs area is located at an altitude of 8,000 ft and has very cold winters, but Zuckerman (personal communication) suggested that some of the introduced species have the potential to spread downstream and reach other thermal refugia during warmer months.

Voucher specimen(s): reportedly were deposited with the U.S. Fish and Wildlife Service, Fort Collins, Colorado (Zuckerman, personal communication); but we have not been able to locate this material.

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.

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

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, editor. 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 Hemigrammus ocellifer

Author: Nico, L.

Peer Review Date: 11/13/2003

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.