Microhabitat association is a key factor contributing to the diversification of coral reef fishes. For species with specific microhabitat associations, a change in host organism (a coral, sponge, or other organism) on a reef could enable sympatric speciation, where a new species evolves in the same geographic area as the ancestral species. The tusked goby, Risor ruber, is a poorly studied obligate sponge-dwelling coral-reef fish. Preliminary genetic data on R. ruber indicate that there are eight genetically distinguishable lineages based on mitochondrial DNA sequence data and that these linages often live on specific host sponges, pointing to a possibility of ecologically-driven speciation. This study aims to uncover potential connections between morphology, microhabitat, and genetics, by determining if the morphological variation of the recurved canines and other morphological features, such as body length versus depth, correspond with the genetic lineages identified and their host sponge preferences. Measurements will be taken from CT scans and preserved specimens. Fin counts, vertebral counts, and teeth will be examined on cleared and stained specimens. Results of this study may lead to new species descriptions within the genus Risor.