The review summarizes both the authors' own and published data on the fatty acid composition of lipids in high latitude marine aquatic organisms connected by food relations. Special attention was paid to the content of specific fatty acids in Leptoclinus maculatus larvae, distinguishing them from adults. Fry accumulated specific fatty acids, derived from food over the short Arctic summer, in the neutral lipids stored in the lipid sac and muscles. The storage of energy lipids by larvae represents a physiological and biochemical mechanism of fish adaptation, which predetermines the life strategy and guarantees the survival of the larvae in the Arctic.