I already use the water with the water that I suck out of my tank during water changes. It is rich with nitrates and phosphates. Fish food is basially fish meal. Here is some info from the back of the can: Crude protein 29% arginine 1.21% Histidine 0.63% crude fat 5% Crude fiber 2% and ascorbic acid 200mgs.
Fish meal, wheat flour, rice flour, potato starch, Dehulled soybean meal, shrimp meal, fish oil, sor protine isolate, corn gluten meal, ground dried tomato, brewers yeast, wheat gluten meal, lecithin, marigold petal extracy, choline chloride, xanthan gum, dl-mehionine, Vitamin A, D3, E, B12, Riboflavin, Niacin, Calcium, Menadione Sodium Bisulfite complex, folic acid, pyridoxine hydrocloride, thiamine mononitrate, biotin, yeast extract, zinc sulfate, managnese sulfate, copper sulfate, potassium iodate, sodium selenite, and cobalt carbonate.