Primary production is considered the major factor controlling the successfulness of milkfish culture in the shallow water system.Experiments wereconducted in aquariums to study the energy conversion between benthic algaeand solar input within saline water.Empirical relationship between energyassimilation and heat content within algae was found equal to 0.5154 kiloeinstein to 1 kcal.Rates of oxygen consumption by fish of different sizeswere estimated by a respiratory chamber.Results of data analysis gavesolutions to the Winberg metabolism equation,with a metabolic rate of changeequal to 0.83.Combining the experimental results with other informationallowed the preparation of an energy budget for the farming system.Theresult gave theoretical explaination for the requirement of supplementalfeeding,and potential improvement for the shallow water system.