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.

Rhodeus sericeus
Rhodeus sericeus

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Rhodeus sericeus (Pallas, 1776)

Common name: Bitterling

Synonyms and Other Names: bitter carp, European bitterling

Taxonomy: available through www.itis.govITIS logo

Identification: Distinguishing characteristics were provided by Berg (1949), Moore (1968), and Page and Burr (1991). Keys were included in Berg (1949) and Moore (1968). Illustrations or photographs appeared in Berg (1949), Maitland (1977), and Axelrod et al. (1985). Another name used for this species is . Berg (1949) apparently recognized two species: R. s. amarus and R. s.Rhodeus amarus sericeus.

Size: 11 cm.

Native Range: Europe from the Seine and other rivers of France eastward to Asia Minor, and northern China (there is a very wide geographical gap in the northern part of the Asian continent separating the ranges of the two subspecies) (Berg 1949; Lee et al. 1980 et seq.).

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

Nonindigenous Occurrences: The first records of this species (as Rhodeus amarus) were from the Sawmill River, a tributary of the Hudson River, at Tarrytown, Westchester County, New York in the early 1920s (Dence 1925; Myers 1925; Bade 1926). Although Breder (1933) claimed it disappeared from this locality shortly after 1925, additional specimens were taken in subsequent years (Greeley 1937), with the last collection made in 1951 (Schmidt et al. 1981). Two specimens were taken from the Bronx River at Bronxville, Westchester County, New York, in 1933 (Greeley 1937); subsequent collections indicated the species was established in a localized reach of the river (Lee et al. 1980 et seq.; Schmidt et al. 1981; Schmidt and Samaritan 1984; Smith 1985).

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 Rhodeus sericeus are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
NY192319963Bronx; Lower Hudson; Middle Hudson

Table last updated 3/1/2024

† Populations may not be currently present.

Means of Introduction: Probable aquarium release (Myers 1925; Bade 1926; Lee et al. 1980 et. seq.; Schmidt et al. 1981).

Status: Established in the Bronx River, New York, since at least the early 1930s (Greeley 1937; Schmidt et al. 1981; Smith 1985). Previously established and abundant in Sawmill River, New York; that population is assumed to be extirpated (Schmidt et al. 1981).

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: Rhodeus requires freshwater bivalves as spawning sites; eggs are deposited, fertilized, and hatch in live mussels. Laboratory evidence has shown that this European fish will use certain U.S. native mussels (Anadonta cataracta and Unio complanatus) (Breder 1933). The reported recent decline in population of bitterling in the Bronx River apparently has resulted from a declining freshwater mussel population brought about by water pollution (R. Schmidt to Courtenay, personal communication).

Voucher specimens: New York (AMNH 39116, 39117, 42444; CU 5112, 23611, 26823, NYSM 11744, 11746).

FishBase Summary

Author: Leo Nico, and Pam Fuller

Revision Date: 4/30/2018

Peer Review Date: 12/5/2003

Citation Information:
Leo Nico, and Pam Fuller, 2024, Rhodeus sericeus (Pallas, 1776): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=643, Revision Date: 4/30/2018, Peer Review Date: 12/5/2003, Access Date: 3/1/2024

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 [3/1/2024].

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