Zebrafish have become a popular animal model for behavioral neuroscience (Gerlai, 2014). Recent studies have demonstrated that brief experimental handling prior to euthanizing animals can subsequently alter biological measures quantified post-mortem (e.g. cortisol levels) (Ramsay et al., 2009; Tran et al., 2014). Here we provide a detailed protocol for a simple 30-sec net stressor task for adult zebrafish that increases whole-body cortisol levels without altering the levels of whole-brain dopamine, 3, 4-dihydroxyphenylacetic acid, serotonin, and 5-hydroxyindoleacetic acid (Tran et al., 2014).