How big does an aquaponics system have to be?

The best thing about aquaponics is that there is literally no size criteria.  You can do aquaponics on a tiny scale with a betta fish or a couple of guppies.  The fun potential goes up a ton though when you can go to a 20 gallon tank or larger.  Hard to call yourself a farmer with a guppy and basil plant!  But add twenty fish or so to a tank and raise a dozen plants and it gets interesting.  Start to do a hundred gallons or more and your production reaches a point where your neighbors love you for all the fresh greens you share.  Or you can get huge and go commercial.  Using roughly 10% of the space and water of traditional farming you don’t need a lot of land to put yourself into production.