ABSTRACT
Two experiments were conducted for 6 months to declare to what extent the artificial feed could serve in addition to the optimum fertilizer dose [urea and superphosphate] in polyculture fish ponds. The water quality parameters of different ponds were monitored and analyzed every twenty weeks during the growing period. The results showed a significant differences in fish performance of Tilapia. The high values were obtained from the fish fed balanced diet with fertilizers. Moreover, the high protein efficiency ratios [PER] were obtained from fish fed wheat bran with or without fertilizers, as the feed efficiency decreased linearly with increasing protein level in the diet. In case of carp, significant differences were found in fish performance. The high values were obtained from fish fed balanced diet with or without fertilizers. The highest PER values were obtained from fish fed wheat bran without fertilizers. Concerning the water quality, obvious changes in the nutrient salts and dissolved oxygen were observed. Nitrogen as nitrate proved to be phytoplankton limiting growth, however phosphorus as orthophosphate showed the opposite. These changes can be attributed to phytoplankton blooms and crashes. Economically, highest net revenue was obtained by using balanced diet with optimnum doses of fertilizers, followed by balanced diet only