It isn't just us-fish also react badly to Prozac (fluoxetine). The antidepressant makes them more aggressive, and alters their behaviour.
Male minnows exposed to the drug for four weeks become far more aggressive, and start attacking the female fish. In one group, just a third of the female fish had survived, whereas normal survival rates are closer to 90 per cent. The fish that died had visible bruising and tissue damage.
Reproduction, mating, general activity and levels of aggression were all affected by Prozac, say researchers at the University of Wisconsin-Milwaukee.
The only good news was that the fishes' behaviour returned to normal once the drug was removed from the water. Sadly, that is not an option for fish in rivers and estuaries that are constantly exposed to pharmaceuticals such as Prozac that are flushed down the toilet. The researchers fear that fish colonies are being badly affected by the practice.
(Source: Aquatic Toxicology, 2014; 151: 77)