We do not recommend feeding animal droppings to the fish. They may contain e-coli which may contaminate your system. The commercial fish food is cheap but probably contains GMO. Fishkis.com sells an organic, non GMO fish food. You can grow your own Duck Weed for fish food which is grown on the surface of the water of one of your tanks. You squeeze the water out and freeze it for food. You could also grow worms to feed them as well.