Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Vibrio fischeri is a gram-negative rod-shaped bacterium found globally in marine environments.V. fischeri has bioluminescent properties, and is found predominantly in symbiosis with various marine animals, such as the bobtail squid. It is heterotrophic and moves by means of flagella. Free living V. fischeri survive on decaying organic matter (see saprotroph). The bacterium is a key research organism for examination of microbial bioluminescence, quorum sensing, and bacterial-animal symbiosis.