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.

Metynnis sp.
Metynnis sp.

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Metynnis sp. Cope, 1878

Common name: metynnis

Synonyms and Other Names: silver dollar

Taxonomy: available through www.itis.govITIS logo

Identification: The genus Metynnis is in great need of systematic revision. One of the few available keys was given by Géry (1977). According to Géry, the M. lippincottianus-maculatus complex seems to comprise several different forms that could represent subspecies or sibling species. A possible synonym is M. roosevelti, a name commonly used by aquarists (Géry 1977). Although members of the genus Metynnis are characterized by their long-based adipose fins, those belonging to the M. lippincottianus-maculatus complex superficially resemble young pacus (i.e., Colossoma and Piaractus species) as well as certain piranha species. Other genera of superficially similar 'silver dollars' imported for the aquarium hobby include Mylossoma and Myloplus. Photographs of several Metynnis species appeared in Axelrod et al. (1985) and Sakurai et al. (1993).

Size: 12 cm.

Native Range: Tropical America. Metynnis species are found throughout much of tropical South America (e.g., in the Orinoco and Amazon basins). The M. lippincottianus-maculatus complex is native to Guaporé and Amazon basin (Géry 1977).

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

Nonindigenous Occurrences: A member of this genus was collected in Florida from a lake on Marco Island, Collier County in January, 1980 (FSBC 19822; listed as Metynnis lippincotianus in Courtenay et al. 1984, and as Metynnis sp. in Courtenay and Stauffer 1990 and in Courtenay et al. 1991). A reproducing population was found in Halpatiokee Regional Park Conservation Area in Martin County in 2005, with additional specimens taken in 2006 and 2007 (Shafland et al. 2008; Florida Fish and Wildlife Conservation Commission 2009). In Kentucky, a single fish (originally identified as a piranha and as Metynnis roosevelti) was taken by hook and line from Lighthouse Lake, Louisville, Jefferson County, in the summer of 1981 (Anonymous 1981; Fossett 1981).

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Metynnis sp. are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
FL198020073Big Cypress Swamp; Florida Southeast Coast; South Atlantic-Gulf Region
KY198119811Silver-Little Kentucky

Table last updated 7/20/2024

† Populations may not be currently present.

Means of Introduction: Records mostly likely represent aquarium releases.

Status: Reported from Kentucky. Established locally at one location in Florida.

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: Several Metynnis species are popular aquarium fishes. There is considerable confusion surrounding the Kentucky record. In original published accounts, the fish was identified as a piranha, but the scientific name provided was Metynnis roosevelti (= Metynnis maculatus). However, in a photograph of the fish accompanying the newspaper article (Fossett 1981), the specimen actually appears to have a short adipose fin and is probably a pacu, possibly Piaractus brachypomus. The collectors gave the live fish to the Louisville Zoo, where it was kept in aquaria; when the fish later died, it was supposedly not preserved. The Kentucky specimen has been the basis for inclusion of the species in published lists of non-established foreign species, with earlier listings identifying it as Metynnis roosevelti (e.g., Courtenay et al. 1984) and later simply as Metynnis sp. (i.e., Courtenay and Stauffer 1990; Courtenay et al. 1991).

References: (click for full references)

Anonymous. 1981. Piranha caught in Kentucky. Pet Business 7(11):33.

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., D.A. Hensley, J.N. Taylor, and J.A. McCann. 1984. Distribution of exotic fishes in the continental United States. Pages 41-77 in Courtenay, W.R., Jr., and J.R. Stauffer, Jr, eds. Distribution, biology, and management of exotic fishes. John Hopkins University Press. Baltimore, MD.

Courtenay, W.R., Jr., D.P. Jennings, and J.D. Williams. 1991. Appendix 2: exotic fishes. Pages 97-107 in Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. Common and scientific names of fishes from the United States and Canada, 5th edition. American Fisheries Society Special Publication 20. American Fisheries Society, Bethesda, MD.

Courtenay, W.R., Jr., and J.R. Stauffer, Jr. 1990. The introduced fish problem and the aquarium fish industry. Journal of the World Aquaculture Society 21(3):145-159.

Florida Fish and Wildlife Conservation Commission. 2009. Florida FWC exotic database. Provided by L. Connor on 31 October 2009. Florida Fish and Wildlife Conservation Commission, Tallahassee, FL.

Fossett, J. 1981. Here's one that didn't get away. The Courier-Journal, Louisville, KY. 19 June 1981.

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

Sakurai, A., Y. Sakamoto, and F. Mori. 1993. Aquarium fish of the world: the comprehensive guide to 650 species. Chronicle Books, San Francisco, CA.

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:
FishBase Summary

Author: Leo Nico, Pam Fuller, and Matt Neilson

Revision Date: 5/21/2019

Peer Review Date: 4/30/2013

Citation Information:
Leo Nico, Pam Fuller, and Matt Neilson, 2024, Metynnis sp. Cope, 1878: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=423, Revision Date: 5/21/2019, Peer Review Date: 4/30/2013, Access Date: 7/21/2024

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.


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [7/21/2024].

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