Future global food insecurity due to growing population as well as changing consumption demands and population growth is sometimes suggested to be met by increase in aquaculture production. This raises a range of ethical issues, seldom discussed together: fish welfare, food security, human health, climate change and environment, and public concern and legislation, which could preferably be seen as pieces in a puzzle, accepting their interdependency. A balanced decision in favour of or against aquaculture needs to take at least these (...) issues into consideration. It is further argued that in the parallel discussion on increased livestock production animal welfare is an inevitable element both in relation to current legislation in many countries but also in relation to our perception of moral, whereas awareness of fish welfare is low. Both EU legislation and labelling concerning fish is mainly limited to environmental aspects. It is argued that EU shows a split perception of fish, on the one hand acknowledging scientific evidence of fish capacities but on the other excludes fish from detailed legislation. Combining the claim of the Treaty of Lisbon to pay full regard to animal welfare and scientific evidence fish are sentient it is concluded that fish welfare need to be considered in any farming practice and any ethical consideration of increased aquaculture. This might be facilitated taking a basis in our own vulnerability and interdependence, combined with moral responsibility to show sentient beings a ‘loving kindness’—an extension of Cora Diamond’s argument regarding mammals. (shrink)