Pharmaceutical pollution in waterways is having a "disturbing impact" on fish, according to new research.

Psychoactive drugs - including antidepressants - are altering the reproductive behaviour, anxiety levels, and anti-predator responses of fish in the wild, according to Australia's Monash University.

The findings of the impact on the social behaviour of fish has been published in the journal Biology Today.

Dr Jake Martin, from the university's school of biological sciences, said: "Our research found that the antidepressant pollutant fluoxetine (commonly marketed as Prozac) did not alter behaviour of solitary fish.

"But in a group setting, fluoxetine exposure disrupted the frequency of aggressive interactions and food consumption."


He added: "The results are significant because they suggest that behavioural tests in social isolation may not accurately predict the environmental risk of chemical pollutants for group-living species."

According to the research, Prozac didn't change the feeding and foraging behaviour of solitary fish, however when it was applied to whole groups of fish it had a suppressive effect.

Last year, another study covering the impact of Prozac pollution on fish said it could last for three generations, blunting the stress responses in exposed embryos and any of that embryo's descendants once it had matured.

The study, from the University of Ottowa, showed how zebrafish didn't explore their tank as much when they were treated with Prozac.

Dr Vance Trudeau, a neuroendocrinologist, said there were good reasons to believe the effects that his study revealed could also occur in humans.

This is because the core stress hormone cortisone has the same impact in fish as it does on humans.