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Think goldfish are harmless? Not always

Dropping unwanted goldfish into our waterways can wreak havoc, some of them growing to be 16 inches long
20180827-Goldfish Wikipedia
Goldfish, released into Ontario waterways, can grow to be 16 inches in length and be invasive and harmful to other aquatic life. Wikipedia photo

We tend to think of goldfish as tiny, cute and harmless creatures.

While this is usually the case, they can actually be a nuisance, and classified as an invasive species (one of the world’s worst, in fact) if let loose in our lakes, rivers and streams by people who no longer want them.

“Unfortunately a lot of the time people aren’t sure what to do with this fish when they are no longer wanting it or able to keep the fish as a pet so they release it into a local waterbody,” stated Lauren Bell, Invasive Species Centre community education and outreach coordinator, in an email to SooToday.

According to a map supplied by the online Early Detection and Early Mapping System (EDD MapS Ontario) invasive species goldfish don’t appear to be a problem in Sault and area waterways, but are indeed along the north shore of Lake Erie, the west end of Lake Ontario, and, occasionally, in other locations across the province.

However, in what should be taken as a word of caution for our area, Bell wrote “goldfish are a problem in our Ontario lakes...some issues associated with them is they reduce water quality because they stir up mud when they feed, which inhibits the growth of aquatic plants. They can carry diseases which can affect local fish populations (while these diseases do not affect humans). They eat mass amounts of a wide array of foods, grow extremely large, and can reproduce quite well. They can be in direct competition with our native Ontario fish.”

“We always tell people to never release any live fish into lakes or rivers. If you have an unwanted live fish you can return it to a pet store, or donate it to a local school,” Bell wrote.

Dropping unwanted goldfish into waterways can lead to some of them growing up to 16 inches (40 cm) in length and weighing up to four pounds (1.8 kg).

Anyone thinking they’ve spotted discarded, growing goldfish in our lakes, rivers and streams should report it to the EDD MapS Ontario website

For centuries, the goldfish has been a well-known species of fish, sold to aquariums, ponds and water gardens, first kept as pets in China in the 10th century.

They are thought to be the first foreign fish species to be introduced to North America from overseas.


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Darren Taylor

About the Author: Darren Taylor

Darren Taylor is a news reporter and photographer in Sault Ste Marie. He regularly covers community events, political announcements and numerous board meetings. With a background in broadcast journalism, Darren has worked in the media since 1996.
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