Keep an eye out for invasive fish while you’re ice fishing this winter or enjoying fishing in the summer. Invasive fish outcompete native fish and disrupt the aquatic food web. Impacts of invasive fish can reduce fish populations which can have negative effects on the fishing industry. 
Invasive fish can be intentionally introduced as sport fish or food sources, or dumped into waterways as unwanted aquarium pests. They can also be unintentionally spread by the bilge water of boats or by people who unknowingly use an invasive juvenile fish as bait. 
You can help by keeping an eye out for invasive fish and reporting sightings. Learning of the presence of invasive fish early on before populations grow will reduce their impacts and strengthen management efforts. 
How You Can Help:
  • Learn to recognize invasive fish threatening the St. Lawrence Eastern Lake Ontario region.
  • Keep an eye out for invasive fish while fishing and enjoying the water.
  • Report sightings of invasive fish you encounter to
  • Dispose of unwanted aquarium animals and plants in the garbage, not in waterbodies. 
  • Use local bait and dispose of unused bait in the trash or above the waterline on dry land. 
  • Clean, drain and dry your boat and equipment. 
Northern snakehead and tench are two invasive fish that are not yet known to be established in the St. Lawrence Eastern Lake Ontario region but could easily be spread to the area.
You can help by keeping an eye out for these species and reporting sightings.

Northern snakehead (Channa argus) is a predatory fish that when established can have a significant impact on aquatic food webs, native fish populations, as well as the fishing industry.

Native bowfin and burbot can be easily confused with northern snakehead. However, snakehead has a much longer anal fin than the bowfin, and snakehead has a continuous dorsal fin whereas the burbot has a double dorsal fin.   and these native fish. 

People can help stop the spread of northern snakeheads by not using them as bait and by draining and cleaning the water-containing compartments on their boats. 

If you believe you have caught a northern snakehead:
  • Kill it immediately (remember, it can survive on land) and freeze it.
  • If possible, take pictures of the fish, including close ups of its mouth, fins and tail.
  • Note where it was caught (waterbody, landmarks or GPS coordinates).
  • Report it to your regional NYS DEC fisheries office or to NYS DEC’s Invasive Species Bureau at or (518) 402-9425.
  • You can also submit a report through iMapinvasives.

Tench (Tinca tinca) are invasive fish in the minnow/carp family. They are generalist predators and have the ability to diminish aquatic food-webs, increase water turbidity, and introduce non-native parasites. 

Tench can grow up to 18 inches in length and weigh up to 10-12 pounds. They have dark olive to pale golden coloring with a white bronzy belly and bright reddish-orange colored eyes. Their fins are distinctively rounded and dark-colored with no spines. 


If you believe you have caught a tench:
  • Note your location.
  • Do not release the specimen, put it on ice.
  • Take close-up photos of the specimen.
  • Notify the SLELO PRISM Program Manager Rob Williams at

Did you enjoy this blog post? Take our Pledge to Protect and get monthly emails showcasing actions you can take to protect your favorite hiking trails, paddleways, forests, garden, and community from the impacts of invasive species!

Take the Pledge to Protect

The Pledge-to-Protect is a fun, positive, inviting, engaging and rewarding way to participate in invasive species prevention and management.


Here’s How It Works:
  1. Fill out the pledge form below and select the outdoor areas you spend the most time in.
  2. Check your inbox for your confirmation email.
  3. Explore the resources in the virtual toolkits or download the PDFs.
  4. Earn a virtual badge for each pledge you take.
  5. Every month, you’ll receive a special Pledge-to-Protect email about a prevention/management activity to help you fulfill your pledge OR a highlight of an invasive species to keep an eye out for.
First and Last Name(Required)
What will you protect?(Required)
Chose the pledge category that you spend the most time in or that you're the most interested in learning of applicable prevention and management actions you can take while enjoying these environments.
This field is for validation purposes and should be left unchanged.