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Invasive Species: Bitterling


(Rhodeus sericeus)
*Not detected in Michigan*


Report this species:

Use the Midwest Invasive Species Information Network (MISIN) online reporting tool.

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  • Small, average length is 6-7 cm.
  • Grey-green back with silvery white sides and belly.
  • Metallic streak on the hind end of the sides.
  • Pale orange fins with gray shading.
  • Mouth is oblique, inferior, or just terminal.
  • Lower jaw is never longer than upper.

Photo courtesy of George Chernilevsky.


Habitat: Bitterling occur in marshes, lakes, ponds, muddy/sandy pools, and backwaters of rivers.

Diet: Diet includes small larvae of insects along with plant material.

Native Range: Areas of Europe from the Seine River in France to Asia Minor and northern China.

Local Concern: Bitterling need freshwater mussels to reproduce. Females lay their eggs between the gills of bivalves. The eggs are then fertilized by the male and hatch inside the live mussel. The fish rids the bivalve of parasites, resulting in a symbiotic relationship. Reported declines in bitterling populations in the Bronx River may be the results of a decline in populations of native freshwater mussels due to water pollution.

U.S. Distribution: Introduced and established in the Bronx River, New York.

Potential Means of Introduction: Aquarium release.


Bitterling Invasive Species Alert (printable PDF)