Invasive Species

Thousands of goldfish were spotted in March in Teller Lake #5 off Arapahoe Road in Boulder, Colorado, and biologists are concerned. Here's a look at the fish-filled lake.

Killer shrimp, creatures that indiscriminately slay other animals without eating them, may soon join the list of invasive species living in the Great Lakes, a new study finds.

Straying from the trail, hikers can spread invasive species deep into the woods.

Once down to only 15 animals, giant tortoises on Espãnola, a tiny Galápagos island, now number about 1,000, making the reptile one of conservation's greatest success stories.

An amazing video from the Florida Keys shows a curious domestic cat nearly become a midnight snack for an American alligator.

An invasive species of camel cricket from Asia is now far more common in American basements than the native variety, a citizen science project found.

When other predatory fish quit stalking their prey to look for easier targets, lionfish just keep on killing.

A genetic modification that creates male-only populations could give us a new weapon against invasive fish such as carp that plague our waterways.