Objective The zebrafish (Danio rerio) is emerging as a useful behavioral model of human anxiety.Here we further ascertain zebrafish larvae models of anxiety and validate the pharmacological effects of neuroactive compounds by the light/dark preference test.Methods We provide a detailed description of the pattern of exploratory behaviours encountered in zebrafish larvae when exposed to the light/dark preference test.We find that the larvae spend less time in the dark compartment relative to the white compartment of the testing apparatus.The expression of these dark-avoidance behaviours was significantly attenuated by anxiolytic (diazepam, lorazepam) drugs.Results The findings ascertain the nature of dark-avoidance behaviours as anxiety-like behaviours and provide the pharmacological validation of the light/dark preference test for zebrafish larvae.This behavioural based assay can accommodate drug screening of neuroactive compounds.