Anti-Social Fish: Drugs To Blame

Anti-social fish may be the next big challenge coming to your favorite fishing hole. According to Patrick Walter at Chemistry World, Swedish scientists have determined that a surprisingly small amount of common anti-anxiety drugs can have an unexpected effect on fish behavior.

Swedish scientist Tomas Brodin, along with several colleagues, has published evidence in Science that even a tiny amount of Oxazepam, an anti-anxiety drug, can change the behavior of European perch. The fish were certainly less anxious about getting into the space of others in their tank. Walter reports:

“Fish exposed to the drug at similar levels to those found in Europe’s and America’s waterways were around 50% more active and significantly less social. Perch swimming in waters with a much higher drug dose of 910µg/l were also more active and less friendly, and also much, much bolder.”

While anti-social fish may not seem much of a worry at first glance, in the grand scheme of things, the pushy perch might hint at larger problems. Brodin believes that the behavior changes could be enough to make the affected fish easier prey for predators because they are less likely to hide.

Bullies are presumably not any more attractive to other fish than they are to humans, so it’s possible that they will have also more trouble finding high quality mates, which could have “evolutionary” consequences, according to the Swedish scientists.

The National Institutes of Health explains that Oxazepam is an important prescription medication used in the treatment of severe anxiety and withdrawal from alcoholism. As Dusten Carlson has previously reported, untreated anxiety can actually kill.

No one is suggesting that patients do without a critical medicine in order to prevent anti-social fish from going on a rampage. “The solution to this problem isn’t to stop medicating people who are ill but to try to develop sewage treatment plants that can capture environmentally hazardous drugs” explains Jerker Fick, who co-authored the study with Brodin.