Eric I agree with what you are saying but for what ever the reason either by feeding the forage or by feeding the fish themselves the growth rate increased significantly when I went to the higher protein food. It could be that the lower priced food lacked some other nutrient that the purina aquamax gave the fish. I also was reading on the package that they add fish attractants to the pellets to get the fish to eat more. One of the things that Bob Lusk kept telling me was that not all protein is equal and to make sure that the first ingrediant is fish meal and that the protein is not coming from plants.