Currently, demands for fish diet components such as fish meal and fish oil have increased under the development of aquaculture worldwide, which results in the rise of fish diet prices. This study formulated seven types of treatment diets using fish by-products, fishery by-catch, and pig blood meal and compared them with a commercial control diet. The manuscript's structure is standard, and the descriptions are clear with almost enough information.I have one major comment and three minor comments on the current version.Major comment:The authors created seven types of “iso-nitrogenous diets of 35% crude protein.” It is appropriate for comparing the costs of seven treatments and the control diets. However, it is also necessary to consider the survival rate or the total weights after the experiments. The survival rates seem to be missing in both the body text and the table.Minor comment 1:The growth curves of O. niloticus are shown in Figure 1. Three sudden drops are recorded for BM50%, B-P100%, and B-P50%. It is advisable to add a brief explanation.Minor comment 2:It is almost obvious that the commercial control diet is the least cost-effective based on Table 7. Even so, it is preferable to explain the relationship between the control and treatments. Is the control diet an “iso-nitrogenous diet” of 35% crude protein just like the seven treatment diets?Minor comment 3:The intended meaning of the following sentence is not clear.“High lipid content in fishery diets is an indication that proper storage at room temperature is essential since this will slow down rancidity.”