Environmental enrichment selectively enhances learning, but not inhibitory control, in juvenile gilthead seabream (Sparus aurata)

Human-driven environmental change and the expansion of aquaculture have altered the ecological, social, and sensory conditions experienced by fish, raising concerns about how captive environments affect behaviour, cognition, and welfare. Environmental enrichment is widely used to mitigate these impacts and may also enhance welfare and cognitive performance in captive animals. However, its effects on executive functions during early developmental stages remain poorly understood in fish. We investigated inhibitory control and learning in juvenile gilthead seabream ( Sparus aurata ) using the cylinder task, a detour paradigm requiring inhibition of a direct response towards a visible food reward. Fish were housed under enriched and non-enriched conditions and completed a training phase followed by an inhibitory control test. During training, enriched fish showed a significant reduction in the time until task completion across trials, while non-enriched fish did not, indicating differences in learning. In contrast, inhibitory control performance remained low in both treatments, with no effects of enrichment on success rate or response time. Performance variation was instead explained by trial progression, individual behavioural differences, and developmental factors. Fish tested later in the experiment exhibited shorter response times, consistent with ontogenetic changes. Enriched fish displayed higher feeding contact rates, reflecting increased motivation and task engagement rather than improved inhibitory control. Clustering analyses revealed stable individual behavioural profiles predicting task engagement, independently of housing treatment. Overall, environmental enrichment enhances learning and motivation in juvenile seabream but does not improve inhibitory control at least at this developmental stage, highlighting the importance of ontogeny, individual variation, and species-specific ecology when assessing executive functions in fish.