Fish-a-Plenty if You Control Who Get's Fed

Imagine you have a pond of fish and you feed them the same amount of food every day. Suddenly you're tasked with making these fish more plentiful, or at least larger, without affecting how much they are fed. This may sound like a problem that can be solved only with a biblical miracle, but a team of researchers has managed pull it off, and without using chemicals, hormones, or other modern "cheats."