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.

Poecilia sp.
Poecilia sp.
(unidentified poeciliid (hybrid))

Copyright Info
Poecilia sp. Bloch and Schneider, 1801

Common name: unidentified poeciliid (hybrid)

Taxonomy: available through www.itis.govITIS logo

Identification: According to Mundy (2005), the shortfin mollies introduced in the Hawaiian islands around 1960 are hybrids whose parental species will never be known with certainty, but that are in the Poecilia sphenops complex (called the Poecilia salvatoris/mexicana species complex in Yamamoto and Tagawa 2000).  They have been previously identified as P. mexicana, P. salvatoris and P. sphenops (Maciolek 1984; Devick 1991; Yamamoto and Tagawa 2000).  Englund et al. (2000) stated that the morphological characters of these shortfin mollies in the Hawaiian Islands are not congruent with any described species but that they are distinctive and apparently do not interbreed with other poeciliids in Hawaii.

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

Nonindigenous Occurrences:

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 Poecilia sp. are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
CA201920212Salton Sea; San Diego
HI195020193Hawaii; Maui; Oahu
NV201620234Lake Mead; Las Vegas Wash; Muddy; Upper Amargosa
TX201820202Buffalo-San Jacinto; San Marcos

Table last updated 6/17/2024

† Populations may not be currently present.

Means of Introduction: Aquarium release.

Status: Established in Hawaii.

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.

References: (click for full references)

Devick, W.S. 1991b. Pattern of introductions of aquatic organisms to Hawaii freshwater habitats. Pages 189-213 in: New directions in research, management and conservations of Hawaiian freshwater stream ecosystems. Proceedings of 1990 symposium on freshwater stream biology and fisheries management, Hawaii Department of Land and Natural Resources, Division of Aquatic Resources, Honolulu, HI.

Englund, R. A., D. J. Preston, R. Wolff, S. L. Coles, L. G. Eldredge and K. Arakaki.  2000.  Biodiversity of freshwater and estuarine communities in lower Pearl Harbor, Oahu, Hawaii with observations on introduced species.  Final Report prepared for the U.S. Navy.  Bishop Museum Technical Report 16: 1-167.

Maciolek, J. A. 1984. Exotic Fishes in Hawaii and Other Islands of Oceania. Pages 131-161 in: W.R. Courtaney, Jr. and J.R. Stauffer, Jr. (eds). Distribution, Biology, and Management of Exotic Fishes.

Mundy, B. C.  2005.  Fishes of the Hawaiian Archipelago.  Bishop Museum Bulletins in Zoology, Number 6.

Yamamoto, M. N. and A. W. Tagawa.  2000.  Hawaii's Native and Exotic Freshwater Animals.  Mutual Publishing, Honolulu, HI.  200 pp.

Other Resources:
FishBase Summary

Author: Schofield, P.J.

Revision Date: 6/29/2023

Peer Review Date: 2/14/2006

Citation Information:
Schofield, P.J., 2024, Poecilia sp. Bloch and Schneider, 1801: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=855, Revision Date: 6/29/2023, Peer Review Date: 2/14/2006, Access Date: 6/17/2024

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 [6/17/2024].

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