What do home fish eat?

Try your local pet or department store. There should be an area just for fish and packaged "fish food" that most home fish would eat just fine. There are a few different types, but it should be clear on the packaging what size and type of fish the food is made for. If you happen to have a more or less exotic fish (something above and beyond the usual Goldfish or other commonly available pet fish from the store) you may wish to check with a greater authority on that particular species.