In the squid-vibrio system, bacterium Vibrio fischeri colonized the light organ of Hawaiian bobtail squid Euprymna scolopes, but the process of how and why multiple strains colonize the host is unknown. Bacterial isolates from a single wild caught squid were subject to colonization and motility assays to determine whether motility heterogeneity gives rise to multi-strain symbioses. Isolates are shown to be diverse in motility and able to colonize squid independently.