By Joe Cermele

There have been many studies conducted on the effects of various contaminants on fish in waterways all over the world, from nuclear waste, to cosmetic residues, to crude oil. But up until I found this article in the New York Times, I’d never given any thought to how much antidepressant medication can end up in lakes and rivers, and what effects human happy pills might have on fish. And guess what? According to a study outlined in the story, Zoloft, Prozac, and all those other meds that make us happy make fish happy too…kind of.


To get a better understanding of how psychiatric drugs in waterways effect fish, a research team in Sweden exposed perch to the drug Oxazepam, which, per the story, is commonly found in varying levels in rivers around the globe. Oxazepam gets there by being flushed, discarded, or excreted.

The team started with perch from the Fyris River that already had traces of Oxazepam in their tissue. After hatching baby perch from the roe of the collected fish, they set up tanks and exposed each test group of babies to different amounts of the drug. Here’s what they found:

The more Oxazepam [the perch] ingested the more active the fish were, measured by the number of swimming motions in a 10-minute period. They were also less social, spending less time near a section of the tank with other fish and more time near an empty compartment. And they were quicker to grab and eat zooplankton. At the highest Oxazepam concentration, fish were also bolder, measured by how long it took them to leave a box [marked off] in the tank and explore new territory.

So are antidepressants good for fish? Not really. Those changes in behavior are still unnatural and could have long-term negative effects on fish populations. But in the short term, I guess if you happen to find a river with higher levels of happy juice, that 7-pound smallie or 50-inch muskie might be more likely to take a swing at your lure, and smile at your while they’re doing it. I can just hear the guys who gave us Berkley Gulp! scheming right now. Have a great weekend.