I've created a new page called Aquaponics Extras to hold a few Special Topics regarding Aquaponics and i'll start off with the Duckweed topic. Duckweed is an easy, cheap and abundant food source for fish. Its very high in protein (~40%) and could clean off waste water as well.
The reason i open this Special Topic is to learn about Duckweed myself since i intend to farm this plant for my fishes (tilapia likes duckweed a lot) . Duckweed has high growth rate (doubles in 3 days) and this creates FREE fish food and saves me a lot of money from buying fish feed.