The concrete goal of CIRCOLIE is to help Flemish feed companies make more sustainable aquaculture feeds. Within CIRCOLIE, the focus is entirely on oil as an ingredient in fish feed. This is because this ingredient often includes fish oil and/or soybean oil, which, for well-known reasons, are not sustainable (supply from outside Europe, overfishing, loss of rainforest,... (Boyd et al., 2020)). Using translation research, we convert knowledge about specific oils in other animal species and in fish into combinations of oils that can replace non-sustainable oils such as fish oil and soybean oil. These combinations should not only make the feed more circular and local, but also give it a certain functionality. Functionality means that the feeds bring about increased intestinal health, immunity in the fish or even give better taste to the fish fillet. An economic analysis should give us insight into the production cost of the feed and in the second instance the feed cost in fish production.