Gigantic Goldfish

When some goldfish owners no longer want their pets, they dump the fish into local waterways. In a tank, the fish stay relatively small. But in the wild, goldfish can grow to enormous sizes. This summer, officials removed dozens of massive goldfish from a lake near Burnsville, Minnesota— some were more than 38 centimeters (15 inches) long!

Goldfish are native to China and East Asia. In many places across the U.S., they have become an invasive species. These non-native organisms can harm the local ecosystem—a community of organisms interacting with their environment. With that in mind, “only buy a new pet fish if you’re sure you want to keep it,” says Chelsey Blanke, a researcher at the Minnesota Department of Natural Resources.