Background: Health recommendations advocating increased fish consumption need to be placed in the context of the potential collapse of global marine capture fisheries. Methods Literature overview. Results: In economically developed countries, official healthy eating advice is to eat more fish, particularly that rich in omega-3 oils. In many less economically developed countries, fish is a key human health asset, contributing ?20% of animal protein intake for 2.6 billion people. Marine ecologists predict on current trends that fish stocks are set to collapse in 40 years, and propose increased restrictions on fishing, including no-take zones, in order to restore marine ecosystem health. Production of fishmeal for aquaculture and other non-food uses (22 MT in 2003) appears to be unsustainable. Differences in fish consumption probably contribute to within-country and international health inequalities. Such inequalities are likely to increase if fish stocks continue to decline, while increasing demand for fish will accelerate declines in fish stocks and the health of marine ecosystems. Conclusions: Urgent national and international action is necessary to address the tensions arising from increasing human demand for fish and seafood, and rapidly declining marine ecosystem health.