Tinca tinca


Tench (Tinca tinca) are an invasive fish native to Europe and Western Asia. They are a member of the minnow/carp family Cyprinidae and were introduced to the U.S. as a food and sport fish.


Tench was illegally introduced by an unlicensed fish farm in the 1980s to the Richelieu River, a tributary of the St. Lawrence River. It is currently found in the Columbia watershed in British Columbia and is well established in the U.S. Mississippi River Watershed. There is concern Tench may spread further south on the St. Lawrence River and eventually enter Lake Ontario and other Great Lakes.


Tench inhabit weedy/muddy water bottoms. They have high reproductive rates, long lifespans and can survive in low-oxygen environments. They are generalist predators whose diet includes fish eggs, snails and other benthic invertebrates which puts them in direct competition with many native fish species. Tench have the ability to diminish aquatic food-webs, increase water turbidity, and introduce non-native parasites into the Great Lakes. Early detection of Tench is extremely important in preventing its spread into the Great Lakes basin.



Tench can grow up to 18 inches in length and weigh up to 10-12 pounds.

Color/ Description

Tench have dark olive to pale golden coloring and a white bronzy belly and bright red/orange eyes. They have a terminal mouth with a barbel at each corner. Fins are dark-colored and rounded, with no spines.


You can help stop their spread by learning how to recognize Tench and keeping an eye out for this fish. Help find tench by joining our Invasive Species Surveillance Volunteer Network

Search for Tench in the St. Lawrence River between Cape Vincent and Massena, NY. Pay special attention to waterbodies near farming ponds. Golden colored Tench varieties are popular aquarium species.

Do not use Tench as bait. Never release unwanted pets or dump unused bait into waterways, doing so may spread invasive species. 

If you think you have found Tench:

Note your location.

Don’t release the specimen, put it on ice.

Take close-up photos of the specimen.

Notify SLELO PRISM at 315-387-3600 (x 7725) rwilliams@tnc.org

Outreach Material: 

Tench Poster

Tench Brochure

Additional Resources: 

Eurasian Tench (Tinca tinca): the next Great Lakes invader, by Sunci Avlijas, Anthony Ricciardi and Nicholas E. Mandrak

Intentional Introduction of Tench into Southern Quebec, by Pierre Dumont, Nathalie Vachon, Jean Leclerc, Aymeric Guibert

La tanche, Quebec ministry of forests, wildlife and parks

Tench, Ontario government

Photo credits: 

Title photo by Alan Butterworth www.bugwood.org

Side by side photo retrieved from Invadingspecies.com

Tench in hands photo by Sunci Avlijas www.bugwood.org


Prevent the introduction of invasive species into the SLELO PRISM.

Rapidly detect new and recent invaders and eliminate all individuals within a specific area.

Share resources, including funding personnel, equipment, information, and expertise.

Collect, utilize, and share information regarding surveys, infestations, control methods, monitoring, and research.

Control invasive species infestations by using best management practices, methods and techniques to include: ERADICATION (which is to eliminate all individuals and the seed bank from an area), CONTAINMENT (which is reducing the spread of established infestations from entering an uninfested area) and SUPPRESSION which is to reduce the density but not necessarily the total infested area.

Develop and implement effective restoration methods for areas that have been degraded by invasive species and where suppression or control has taken place.

Increase public awareness and understanding of invasive species.

Develop and implement innovative technologies that help us to better understand, visualize, alleviate or manage invasive species and their impacts or that serve to strengthen ecosystem function and/or processes.

Rob Williams                              rwilliams@tnc.org                     Program Director

Megan Pistolese megan.pistolese@tnc.org
Outreach and Education

Brittney Rogers brittney.rogers@tnc.org 
Aquatic Invasive Species

Robert Smith       robert.l.smith@tnc.org 
Terrestrial Invasive Species

Zachary Simek    zachary.simek@TNC.ORG     Conservation and GIS Analyst

During this time the best way to contact our team is via email.