Concern about the collapse of overexploited fish populations and the safety of consuming seafood can complicate determining what types of fish are best to eat. In recent years, public attention has become increasingly focused on oceanic environmental contaminants, which may be toxic to seafood consumers in sufficient doses. Laudable education campaigns have been established to inform consumers about seafood choices that are sustainable, and to provide information on which fish are deemed safe for human consumption. We found that unsustainable seafood items also present higher health risks (as indexed by mercury concentrations) and do not necessarily provide greater health benefits (as indexed by omega-3 fatty acid concentrations) as compared with sustainable seafood items. Our results have broad implications for identifying effective approaches for informing consumers about the health risks and benefits of different seafood choices, while simultaneously addressing the ecological consequences of fishing and fish farming.