An interesting story of tossed out goldfish in a lake and its consequences. 
 
The most likely culprit behind the invasive species? Pet owners who illegally dumped goldfish, officials say.
Now the organization is removing goldfish from the lake — by the truckloads. An estimated 500,000 goldfish are in the lake, uprooting plants and fighting with native fish for food, officials say. They can live up to 25 years, reproduce rapidly and survive through the frigid Minnesota winters.
 
https://www.kansascity.com/news/nation-world/national/article246986872.html