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.

Betta splendens
Betta splendens
(Siamese fighting fish)

Copyright Info
Betta splendens Regan, 1910

Common name: Siamese fighting fish

Synonyms and Other Names: betta, beta

Taxonomy: available through www.itis.govITIS logo

Identification: Witte and Schmidt (1992) discussed the genus and provided an identification key to species. They treated B. splendens as a valid species, but also recognized a B. splendens species complex. Many color variants have been developed by aquarists. See Axelrod et al. (1985) for color photographs of live fish.

Size: 6 cm.

Native Range: Tropical Asia. Native to Southeast Asia including the northern Malay Peninsula, central and eastern Thailand, Kampuchea, and southern Vietnam (Witte and Schmidt 1992).

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

Nonindigenous Occurrences: Specimens ranging from 1-3 cm were taken from the Thames River drainage in Connecticut (Whitworth 1996). Specimens were collected from Lake Worth Drainage District canal L-15, adjacent to an aquarium fish farm west of Atlantis in Palm Beach County, Florida (Ogilvie 1969; Courtenay et al. 1974), but have not been found at that locality in subsequent years (Courtenay and Hensley 1979). A population became established in a canal south of Holmberg Road in Parkland, northern Broward County. When first discovered in December 1975, it was a dominant fish; however, the population was killed by extremely cold weather in January 1977 (Courtenay and Hensley 1979; Courtenay et al. 1984; Courtenay and Stauffer 1990). A single specimen was collected in the headwaters of Gamble Creek, near Parrish (UF 118475).

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 Betta splendens are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
FL196919903Florida Southeast Coast; Manatee; South Atlantic-Gulf Region

Table last updated 4/21/2024

† Populations may not be currently present.

Means of Introduction: Florida records are the result of probable escapes from local ornamental fish farms (Courtenay and Stauffer 1990). Connecticut records are probably aquarium releases.

Status: Failed in Connecticut. Shafland et al. (2008b) list it as a formerly reproducing species based on a recent survey (Shafland et al. 2008a).

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: A supposed report of Betta splendens in Hiko Spring, Lincoln County, Nevada, was false (W. Courtenay, personal communication). This species has been shown to be an alternative host to the glochidia of native unionid mussels Lampsilis cardium and Utterbackia imbecillis (Watters and O'Dee 1998). Siamese fighting fish are widely used in studies of animal behavior.

Voucher specimens: Florida (UF 97046, 118475).

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.

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 W. R. Courtenay, Jr., and J. R. Stauffer, Jr., editors. Distribution, biology and management of exotic fishes. Johns Hopkins University Press, Baltimore, 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.

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.

Ogilvie, V. E. 1969. Illustrated checklist of fishes collected from the L-15 Canal (Lake Worth Drainage District) in Palm Beach County, Florida (collection date November 8, 1969). Unpublished Report for the Florida Game and Fresh Water Fish Commission. 10 pp.

Shafland, P.L., K.B. Gestring, and M.S. Sanford. 2008a. Florida's exotic freshwater fishes - 2007. Florida Scientist 71: 220-245.

Shafland, P.L., K.B. Gestring, and M.S. Sanford. 2008b. Categorizing introduced fishes collected from public waters. Southeastern Naturalist 7(4): 627-636.

Watters, T.G. and S.H. O'Dee. 1998. Metamorphosis of freshwater mussel glochidia (Bivalvia: Unionidae) on amphibians and exotic fishes. American Midland Naturalist 139: 49-57.

Whitworth, W. R. 1996. Freshwater Fishes of Connecticut. State Geological and Natural History Survey of Connecticut, Bulletin 114.

Witte, K. E., and J. Schmidt. 1992. Betta brownorum, a new species of anabantoid (Teleostei: Belontiidae) from northwestern Borneo, with a key to the genus. Ichthyological Exploration of Freshwaters 2(4):305-330.

FishBase Summary

Author: Leo Nico, and Matt Neilson

Revision Date: 4/30/2018

Peer Review Date: 10/20/2015

Citation Information:
Leo Nico, and Matt Neilson, 2024, Betta splendens Regan, 1910: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=326, Revision Date: 4/30/2018, Peer Review Date: 10/20/2015, Access Date: 4/21/2024

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 [4/21/2024].

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For general information and questions about the database, contact Wesley Daniel. For problems and technical issues, contact Matthew Neilson.