Microplastics (MP) are ubiquitous in the marine environment and have been shown to alter the behaviour of some species due to potential neurotoxic effect. However, very little is known on the effect of this stressor on behavioural responses of early and more vulnerable life stages. This study explores the effects of polystyrene MP (90 µm diameter) on the foraging activity of newly settled surgeonfish Acanthurus triostegus and on their survival facing predators. Exposure to a high concentration of 5 MP particles per mL (5 MP mL −1 ) for 3, 5 and 8 days did not alter their foraging activity nor their susceptibility to predation. This suggests that short-term exposures to reportedly high MP concentrations have negligible effects on the behaviour of newly settled A. triostegus. Nevertheless, responses to MP can be highly variable, and further research is needed to determine potential ecological effects of MP on reef fish populations during early-life stages.