Pharmacological analysis of zebrafish (Danio rerio) scototaxis

► Preference for dark environments is thought to represent anxiety in zebrafish. ► Chronic, but not acute, fluoxetine had an anxiolytic effect in scototaxis. ► Buspirone had the same effect, but moclobemide did not. ► Benzodiazepines also were anxiolytic in smaller doses, and ataxic at higher doses. ► Ethanol was anxiolytic at the smallest dose, but motor-activating at higher doses.