Hugh,
I would like to offer some additional information about Aquaponics. There are numerous articles available here on SurvivalBlog about this subject, even a Category for it [1]. So this is info in addition to what’s already here.
As mentioned, one of the main potential problems is pumping water around the system. Pumps can take quite a bit of electricity, and they can clog. When they do, (not if, but when) your fish die.
There is a gentleman in Hawaii who has invented (patent pending) a system that can greatly reduce the electrical use and is about as clog proof as you could ask for. His name is Glenn Martinez, and he has numerous videos on You Tube about Aquaponics, along with Natalie Cash (his sister).
Water pump vs Air pumps, that is the question? [2]
This second video is of a demo aquaponics system that shows an air pump in use, providing water movement for up to 30 grow trays. OlomanaGardensAquaponicsSystem [3]