Ok, so who is feeding their fish only duckweed, how much are you raising and feeding, how much input cost do you have in producing your duckweed, what kind of growth are you seeing in your fish?

UF, I guess the point you are trying to make when you say "False" is that duckweed is natural or organic and fish feed is full of GMO corn and chemicals?? This would go back to my original argument for DW if a person is doing it because they want a self sustaining or totally organic system. I can understand that, but it does not make it economically better.
As far as an AP system being natural, it is not, it is a man made ecosystem, just like a zoo or a man made pond, without human input it would die in short order.
Comparing Aquaculture to AP to me is apples and oranges, Aquaculture is competing with cheap imorted fish and expects no secondary source of income such as produce, only fish. I would never build a AP system if I thought my primary income source would be the fish. This has been proven to not work. Several commercial AP systems I know of all say the same thing, they lose money on the fish sales. This is why they have moved away from high density stocking rates and went to low density stocking rates and focused more on plant production while maintaining minimum fish populations for proper water nutrients.
But that is really for a different thread and a different topic. I just want to see some solid information on how duckweed can be economically produced and beneficial when the time, and input cost are factored in, because I just do not see it.