Many studies have shown that personal care products, like toothpaste, shampoo, and other drugs that we use and get into our wastewater have negatively affected fish populations, disrupting their endocrine systems. But can there be any positive effects? A new study shows that one antianxiety drug that made its way into a lake in Sweden has in fact, positively affected the Eurasian perch population, making them bolder, less social, and more active than unexposed fish, ultimately reducing their mortality rates.