Impaired social interactions are a hallmark of neurodevelopmental disorders such as Autism Spectrum Disorder (ASD). Our own observations in zebrafish and a growing literature reveal that host-associated microbes play a critical role in social behaviors. However, how these microbes are acquired, and the mechanisms of their interaction with social behavior remain unknown. We are taking advantage of the tractable genetics and excellent imaging properties of both zebrafish and their associated bacteria to investigate the properties of bacterial transmission between zebrafish individuals during social interactions. We analyzed the time course of bacterial transmission by testing 1, 3, 6, and 8-hour time points of interaction between two fish, each inoculated with the same species of native bacteria, but expressing different fluorophores. We found that the number of transmission events increased with time, with little to no transmission after only 1 hour of interaction, and up to 40% transmission after 8 hours of interaction. We observed that transmission events were often non-reciprocal, which we interpret as the result of non-reciprocal social interactions between individuals. We also found that features of bacterial transmission differed between the skin and the gut. These results provide a baseline for our future experiments to understand what specific aspects of zebrafish social behavior promote bacterial transmission and how transmission is altered in zebrafish mutants with impaired social interactions.