Prozac Fish Study Shows Minnows Turning Into Killers

A Prozac fish study has revealed that trace amounts of the popular anti-anxiety drug may turn harmless minnows into angry, aggressive killers.

Although the study by University of Wisconsin-Milwaukee’s Rebecca Klaper and colleagues isn’t yet published, Klaper came forward this week to speak out about the urgency of their findings. According to their research, tiny fathead minnows exposed to trace amounts of Prozac in the water became more edgy and aggressive.

Some of the angry fish even killed their mates.

“It’s not just an environmental question but a human question as well,” Klaper told ABC News.

No one’s body is perfectly efficient. When people take anti-anxiety medication, a tiny amount is excreted in the urine and ultimately enters the waterways.

In an extended report in Environmental Health News, Brian Bienkowski noted that over 250 million prescriptions for the anti-anxiety drugs are filled each year.

Now, the UWM research has offered new evidence that the trace quantities of Prozac and other drugs affect fish brains. The males are particularly badly affected, sometimes ignoring or avoiding females.

As I reported in February, a Swedish study also revealed that a surprisingly small amount of common anti-anxiety drugs in the water could create anti-social fish.

Swedish researcher Tomas Brodin and his colleagues looked into the way trace amounts of Oxazepam changed the behavior of European perch. Their disturbing report said:


“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…were also much, much bolder.”

Brodin expressed concern about his findings because he believed the bold, bullying perch were more visible to predators — and less attractive to potential mates. Even fish don’t like bullies.

Now we have evidence that the problem isn’t just caused by one kind of anti-anxiety drug, and it isn’t limited to European perch.

Tiny minnows turning into killers, as shown by the Prozac fish study, might be the tip of the iceberg.

[fathead minnow image courtesy United States government via Wikimedia Commons]