The n-3 fatty acids and the lipid class requirement of larval Sparus aurata were studied by comparing patterns of conservation and loss of lipid levels and their content of selected fatty acid groups in starved (for 6 days) and feeding (fed 17 days on Isochrysis enriched rotifers) larvae. There was a marked decrease in the neutral fraction while the reduction in the polar fraction was more moderate in both feeding and starved larvae. In starved fish the pattern of fatty acid loss (percent decrease in μg/mg of dry weight larvae) in the total, neutral and polar fractions was expressed as n-6 > n-9 > n-3. However, the polar lipid in fed fish exhibited a reverse trend that can be described as n-3 > n-9 > n-6. Docosahexaenoic acid (22:6 n-3) was also observed to be more strongly conserved than eicosapentaenoic acid (20:5 n-3) during starvation but more drawn upon in feeding. The results suggest a larval biochemical strategy to conserve the important n-3 fatty acids during starvation. However, their loss during feeding implies that Isochrysis-enriched rotifers do not provide sufficient levels of these fatty acids for growing Sparus aurata larvae.