In the interest of developing food for all these fishes, am wondering if any work has been done to investigate the use of Moringa, a plant (tree) with higher vitamin and nutrient content than most any other on earth - could it be a supplemental food source for omnivores such as tilapia. A world map of where the Moringa grows matches, almost exactly, the area we know as the 'developing world', and is (there) being developed as a food source for people and livestock. Here is a very comprehensive website is devoted to the plant --
-- Some the best information on the site is in the downloadable 'presentations'.
Also here are some links to bicycle power, which may lead to alternate ways of circulating and pumping water:
More alternative ways towards pumping and finding water: