Symbion pandora is a commensal on Norway lobster (Nephrops norvegicus) with a very complicated life cycle. The species was described very recently and appointed to a new phylum, Cycliophora. Obviously nothing is known about the biology of this animal. The present study investigated the feeding biology of Symbion pandora. This was investigated by offering them two different high quality food items: Algae and mussel. Additionally, incubations with radiolabelled dissolved amino acids were done to estimate the energy contribution from DOM. A specific goal was to quantify the amount of organic matter taken in during one meal and estimate how much this contributes to the total energy requirement of internal budding, production of larvae etc. during the life cycle of the cycliophoran. This was done by autoradiography and radiolabel incorporation.