Fish are rich in multiple micronutrients, essential fatty acids, and protein, providing a powerful contribution to the diets of over 3 billion people, and a particularly valuable source of nutrition for vulnerable and marginalised peoples. Over 90% of the world’s fishers are small scale, the majority of whom live in Africa or Asia, where malnutrition is most prevalent. However, marine ecosystems are amongst those most vulnerable to the impacts of climate change. Climate induced habitat destruction and species relocation mean much of the tropics are projected to experience large declines in catch potentials, while areas closer to the poles are expected to experience gains. These shifts in species abundances and availability impact the micronutrients available to coastal populations, with ramifications to human health, cultural identities, and economies. But, climate pressures are operating on an already uneven playing field. Aquatic food systems generate wealth in centres of wealth. These benefits in turn exert pressures onto lower income regions where aquatic food systems provide critical welfare sustaining functions, such as the provision of livelihoods and nutrient dense foods in areas where these are often lacking. However, when fisheries management can support more sustainable catches, climate induced changes to fisheries can result in increased nutrient yields. Similarly, when fisheries and nutrition policies are sensitive to gender and social difference, aquatic food systems can support more equitable outcomes. Thus opportunities exist to sustain the nutritional benefits of aquatic foods and support more equitable distributions of aquatic food system benefits. These opportunities include investing in local fisheries management, developing policies that acknowledge the structural drivers of injustice, and ensuring coordination exists between fisheries- and nutrition-related policies.