While I won't argue the economics of a low cost farm feed, that's exactly what it is, a low cost farm feed, that consists of low cost ingredients.
I did not get it yet but it is 45% protein and 10% fat and 4% fiber which is about the same as what is in tropical fish flakes.
I could formulate a fish food with those exact same crude percentages, and higher, that consisted of nothing more than terrestrial plant matter, which by & large would rate extremely low in total digestibility for the vast majority of tropical fish species.
As an example, the crude protein % alone doesn't tell you anything about the
quality of the protein (as in how much if any a fish can utilize & assimilate) it's nothing more than a nitrogen value, determined by someone wearing a white lab coat. The true value of any protein is directly related to the amino acid content, which can vary greatly from one ingredient to the next.
Also, while a food may appeal to a fishes olfactory senses & taste buds, the same could be said about soda pop & potato chips, and children. With 10% crude fat content (quite often sprayed on to farm feed after processing) it's little wonder why it appeals to the fish, but that doesn't equate to it being a "good" food.
If I owned a large pond I would use a farm feed (but not Purina), and not in a closed system such as an aquarium.
You asked for feedback, that's mine.