Unless J.W. meant that the vitamins turn into toxins when they start to breakdown then I can't imagine there would be a necessity to throw away food that has a few less vitamins. The stored fish food still has more advantages to the fish even with no vitamins compared to other fish foods. Just having fish based protein in the food makes it better than most of the grain based fish food that others are feeding.

It reminds me of the ridiculous labels on prescription drugs that say you should throw them away in a year. Next thing they are going to tell us that we should drain our fuel tanks if we don't use up the fuel in a week and buy fresh...