Variation in animal behaviour has recently gained traction in understanding variation within physiological traits. Integrating animal behaviour may be particularly important for measuring metabolism as oxygen demand is sensitive to the behavioural state of the individual. For example, a fish exposed to a novel environment may exhibit individual differences in metabolic oxygen demand as a consequence of behavioural responses, such as activity and exploration related to anxiety in an unfamiliar context. On this background, we sought to explore variation in routine metabolism (RMR) as a consequence of novelty to the testing chamber and substrate color – with black representing a low anxiety state and white a high anxiety state – using a repeated measures experimental design to track differences in individual traits across treatments. Finally, as shoaling is thought to reduce predation risk and therefore may influence stress-related responses, we tested a subset of individuals in a third iteration of respirometry with a size-matched conspecific. Contrary to our predictions, we found no difference in RMR with black vs. white substrate; whereas, RMR was significantly higher during the second iteration of respirometry, independent of substrate color. Interestingly, the total oxygen consumption in our paired fish tests was not significantly different from the mean RMR in the initial run, potentially indicating a mollifying social effect. Behavioural data suggests differences in activity/exploration that complement metabolic patterns. Our data indicates individual variation in behaviour, especially in response to novelty, and its impacts on the stability of metabolic measurements.