Abstract: Animals vary in their level of site fidelity and ability (or motivation) to return to a home site when displaced. Homing behaviour may be advantageous when the costs (e.g., associated with traversing a potentially hostile landscape) are outweighed by the collective benefits (e.g., access to resources and stable social interactions) of returning to a home site. Here, we hypothesise that these costs relative to benefits — and hence, propensity to home when displaced — will vary among ontogenetic stages of a small reef fish (the common triplefin, Forsterygion lapillum) in New Zealand. We evaluated site fidelity and homing behaviour of three distinct stages (settlers, juveniles, and adults) of F. lapillum, using experimental displacements of tagged individuals. Settlers use different habitats (canopies of macroalgae) than those used by juveniles and adults (cobbles on the seafloor). To evaluate site fidelity of settlers, we constructed an array of “artificial canopies” at 5m intervals along two parallel transects separated by 100m of reef. We allowed fish to settle naturally to these artificial canopies, then tagged them with elastomer, and returned them to these structures (either to the same artificial canopy or else displaced to another canopy 100m distant). After ~20days, we re-captured ~30% of tagged fish, and of these, none had returned to a home canopy when displaced (indeed, we documented no movement of tagged fish between any of the artificial canopies). We evaluated site fidelity and homing behaviour of older juveniles and adults using a separate experimental translocation of tagged individuals. For this experiment, we collected juveniles and adults from a common site, tagged them with elastomer, and either returned them to their home site or else translocated them different distances (up to 800m) away from their home site. We found that adults were more likely to return to their home site when displaced ≤200m, and juveniles were more likely to remain at release locations. Overall, our results suggest that site fidelity and an ability to successfully return to a home site vary with ontogenetic stage. These findings have implications for intraspecific interactions, and indicate that local site quality may be important for adult stages of the common triplefin. [Copyright &y& Elsevier]