ABSTRACTIn Hawaii, applied feeds account for a high percentage of a prawn farmer' production costs. These applied feeds may be important not only because of direct consumption by prawns, but also because of entrance into the natural food chains, which appear to contribute significantly to prawn nutrition. This paper presents information evaluating the direct and indirect roles of an applied feed in a simulated pond environment as well as the relative contributions of the autotrophic and heterotrophic food chains to prawn growth.Postlarval prawns were placed in large outdoor pools having various combinations of 3 potential food sources—organic detritus, phytoplankton, and applied feed. Results of two 50‐day unreplicated studies, with 3 treatments each, determined that natural foods alone, consisting primarily of a mixture of organic detritus and soil produced growth rates equal to or better than commercial production ponds. The applied feed alone (26% protein), with minimal natural foods and no organic detritus or soil, was unable to support growth rates comparable to the other treatments. The earthen substrate appears to supply a major growth factor lacking in applied feeds.An applied feed to supplement the natural foods produced significantly better growth than that obtained by natural foods alone, although this increase was not dramatic. Growth rates in this system averaged 1.5 cm/mo. Water column phosphate levels as well as carbon and nitrogen levels in the sediment increased in the systems supplemented with feed.Future pond management may require more attention to promoting natural productivity, particularly in the detrital layer. Complementary interaction is desirable between naturally available foods and applied fe