Teleost fish have an unrivalled capacity for adult neurogenesis among vertebrates. New neurons are born and incorporated into the mature brain at a high rate in all major brain divisions. While this phenomenon is well-recognized, there remain considerable gaps in our understanding of how adult neurogenesis is regulated and what role it plays in fish physiology and behaviour. We are interested in how steroid hormones, including endogenous glucocorticoids and exogenous estrogen-like compounds, alter proliferation patterns in the fish brain and the organismal outcomes of these changes.