A method is provided for producing prey organisms such as Artermia and rotifers, for feeding aquacultural organisms in particular at the larval stage. The method comprises cultivating the prey organisms during at least part of their life cycle in an aqueous medium comprising at least one lipid component having a DHA content of at least 30 wt %. The enriched prey organisms preferably have a DHA content of at least 12 wt % of their total lipid content. The prey organisms are suitable feed for larvae of fish including halibut, turbot, bass, and flounder, and crustaceans and molluscs.