According to a study fish are becoming increasingly horny because of massive quantities of unnatural chemicals in the water. Researchers from Monash University found Prozac is making fish hell bent on reproducing. Mosquitofish that were given the drug in a tank spent more time chasing female fish. The higher the dose of the drug, the fish displayed "more frequent copulatory behavior" and spent more time following female fish. The pharmaceutical drugs makes its way into the ecosystem because our water treatment systems cannot filter it out.