Throughout the evolution of fish nutrition science, the importance of dietary arachidonic acid (ARA, 20:4n‐6) has been somewhat overlooked, likely due to the polarizing research focus on docosahexaenoic (DHA, 22:6n‐3) and eicosapentaenoic (EPA, 20:5n‐3) acids. Nevertheless, especially during the past two decades, increasing attention has been paid to the requirements and functions of ARA in fish nutrition, and a number of rele...