The dwarf wedgemussel (Alasmidonta heterodon) is a federally endangered freshwater mussel that once ranged from New Brunswick to North Carolina, but now only exists in isolated populations throughout its diminished range. This study aimed to understand links between fish abundance and dwarf wedgemussel abundance and occurrence in the Connecticut and Delaware watersheds. Specifically, my study objectives were to 1) characterize fish assemblages near dwarf wedgemussel locations and unoccupied locations, 2) determine if dwarf wedgemussel occurrence and abundance are related to abundance of the known host fish species, tessellated darter and other potential host fish species per St. John White et. al. (2017). Two fish repeatedly emerged as indicators of dwarf wedgemussel occurrence and abundance: the tessellated darter (Etheostoma olmstedi) and brown trout (Salmo trutta). Tessellated darter was positively related to dwarf wedgemussel which supports the importance of tessellated darter as a host fish in the wild. The negative relationship between dwarf wedgemussel and brown trout may indicate a difference in habitat between the species or brown trout’s predation upon wild hosts.