In a pond with lots of plants and very few fish you may not need to feed your fish at all. In such conditions they will get enough food from the plants and insects that are in the pond. However, even in these conditions it is a good idea to feed the fish a few times a week on a small amount of food. The fish will learn to come to the surface to feed so that you can check they are ok and ensure that they are getting all of the nutrients that they require.