The soy industry’s involvement in aquaculture is a tale of how far-reaching the influence of a large,powerful, well-organized agribusiness can be. Although soy is an unexpected and unnatural food for fish to eat, the research and outreach funded by the soy industry has propelled it to the forefront of alternative feed research in the aquaculture industry. Because of the widespread concern about fish farming’s reliance on small, wild fish for feed, the industry has been able to position soybeans as an answer to aquaculture’s sustainability problems. Unfortunately, however, feeding soy to fish is far from sustainable. By supporting factory fish farming, the soy industry could not only help to expand an industry that degrades marine environments, threatens wild fish populations and damages coastal communities, it could also extend its own negative impacts.