Studying phenotypic differences of biofilm formation can grant insight into its role close organism interactions. Biofilms have been found to allow bacterial aggregation and initiate symbiosis. This is being investigated through the characterization of eleven V. fischeri strains isolated from the light organ of a wild-caught squid, following symbiosis establishment. Coevolved bacterial strains isolated from a single host likely exhibit different levels of biofilm formation that contribute to the dynamics of multi-strain symbioses.