In aquaculture, marine specimens from lower trophic levels have the potential to serve as alternative food source for farmed fish and invertebrates, replacing traditional meal and fish oils. As natural food source for finfish, marine amphipods are rich in essential fatty acids resembling the fatty acid profile of arctic krill. Diets can heavily impact fatty acid profiles of both fish and invertebrates and thus marine amphipods. To estimate the potential of marine amphipods as alternative feed source for aquaculture species, a better knowledge on the manipulation of their fatty acid is needed. In this study two species of Gammaridea (Amphipoda, Crustacea) and their nutritional value in response to three different feedstuffs were investigated.