An experiment was set up to determine the effect that diet has on the gut microbiota of larval Northern Pike. Of great interest was determining the importance of initial diet, and what differences exist between fish initially fed a natural diet or a common aquaculture diet. Next, what happened to the gut microbial communities when all fish were transitioned to a common second diet? Results from this study could influence future aquaculture / fish rearing practices and also improve our understanding of fish: microbe interactions in nature.