Organismal traits evolve in ecological arenas and can therefore provide important links between ecological processes and macroevolutionary patterns. However, the usefulness of trait-based approaches hinges on the relationship between trait states and ecological function. Fishes are the most diverse vertebrate assemblage on earth and their dominance in marine food webs impacts ecosystem processes such as nutrient cycling and habitat maintenance. The dizzying diversity of fish morphology is thought to primarily reflect how fish function (i.e. how they feed and locomote), rather than the resources they consume. While there are many examples of form reflecting performance, the complex nature of fish morphology means there are also many counter examples of multiple structural configurations performing the same function, as well as functionally diverse morphologies. The relationship between trait diversity and trophic niche is well established within certain taxonomic lineages, but we lack consensus about the structure and generality of these form-function relationships. Here we explore the structure of morphological diversity within the global coral reef fish community and its connection to trophic functions. Using a phylogenetic framework, we assess whether traits that describe body shape can adequately quantify dietary and foraging niche categories. Then, we investigate how differences in species richness between major ocean basins relate to the occupation of functional trait space. Preliminary results suggest that, relative to the Atlantic, higher species richness in the Indo-Pacific is associated with denser morphospace occupation, implying increased specialization or niche packing. Our findings will enable further exploration of the reciprocal processes responsible for the assembly of biodiversity and provide a more nuanced understanding of community composition.