What is a substitute fish food for guppies and goldfish
was thinking dried mash potato flakes could be one of them
You can give them green peas, corn flakes or dry cat food now and then. Remember these do not contain all nutrients needed and they are just snacks, so to be fed occasionally. They can suffer from malnutrition if you feed them so often with these.
Um fish food really isn't that expensive so I would just stick to the healthy fish flakes if I were you.