A fish walks into a pharmacy ... well, not exactly. Fish aren't being prescribed anti-anxiety drugs. But they are experiencing the effects. Researchers have found more than 900 different pharmaceutical ingredients in rivers and streams around the world, though they're not yet sure how this could change the behavior of fish and other aquatic animals in the wild."We can't, you know, dump a bunch of pharmaceuticals into the river," says Jack Brand, biologist at the Swedish University of Agricultural Sciences. Instead, Jack's team did the next best thing – with some surprising results.This episode was reported by NPR science correspondent Jon Lambert. Check out more of his reporting.Want to hear more stories about animal behavior? Email us and let us know at shortwave@npr.org.Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy