Intensive fish production is increasingly important in aquaculture. However, sustainability is highly dependent on production costs and efficient use of resources. Feed, being one of the major costs in fish production in the intensive systems and representing 50-70% of the operational costs (Hasan 2007; Zlaugotne et al. 2022), is also one of the major constraints for industry growth due to limited sources of sustainable raw materials. Although fish meal and fish oil use have been dramatically reduced, they remain the main limiting factor for intensive fish production and the overall sustainability of aquaculture. Further reduction of fish meal in feed for high-value species (e.g., salmon, sea bass) and total replacement in diets of mass-produced lower-value species (tilapia, carp, African catfish) is necessary to make the world aquaculture more sustainable (Rana et al. 2009). In addition, the growing worldwide demand for food also limits the amount of land-based agricultural production of raw materials for fish feed. To maintain the required growth in aquaculture, a large proportion of the feed ingredients should replace with cheaper and more sustainable alternatives from plant, algae, or insect-originated components (Idenyi et al. 2022). However, these changes in feed composition affect some reductions in production. The key challenge is to evolve fish lines (such as trout and catfish) that tolerate low levels of fish meal or fish oil and can utilise the alternative compounds more effectively, and to know the effect of alternative components in different production systems of different species (Le Boucher et al. 2012). This selection has been implemented in African catfish (Clarias gariepinus) during the iFishIENCi project.