Environmental variables can take a pivotal role in structuring fish communities, with the distributional limits of species often being shaped by interactions between their physiology and the physical attributes of their environment. Recent research on pectoral-swimming fishes revealed a strong link between the swimming abilities of species and their distribution across wave energy gradients. Species capable of high sustained swimming speeds dominated wave-swept, turbulent habitats, whereas slower swimmers were either rare or restricted to sheltered locations. While this among-species relationship has now been established for over 100 species occupying both tropical and temperate reef systems, the potential for a single species to adapt their swimming abilities to suit their local environment has remained largely unexplored. This study examined intraspecific variation in the swimming abilities of fishes distributed across a 50 km gradient of wave energy on the Great Barrier Reef. I will discuss the mechanisms that may have given rise to such patterns and explore the wider implications for our understanding of morphological diversification in fishes.