Invasive apple snails continue to spread in San Antonio’s River Walk. Officials are testing new barrier systems to curb reproduction.

Armored catfish are driving manatees out of their warm-water refuges, putting their health at risk. Here’s why it’s happening—and what scientists are doing to help. An invasive armored catfish grazes ...

If I were to flip you the bird left-handed, which I sometimes do to mix things up, you’d notice that my middle finger is crooked, with a bulged knuckle. Why does it look like that? Catfish noodling.