show Abstracthide AbstractVibrio fischeri is a bioluminescent bacterium known for its mutualism with the Hawaiian bobtail squid, Euprymna scolopes. However, symbiotic capacity varies greatly even between closely related strains and does not correlate with phylogeny, making V. fischeri a natural model to study the complex evolutionary dynamics underlying host-microbe symbioses. Here we report the complete genome sequence of V. fischeri strain H905, which was isolated from the E. scolopes habitat. H905 is a planktonic isolate unable to competitively colonize E. scolopes despite close cladal relationship to multiple squid isolates, including model symbiont strain ES114.