Winter Water Garden Prep As the temperature drops it is a good idea to prepare your Water Garden for the winter months. 1) In the colder months only feed your Pond Fish specially formulated winter foods, these are easy for the fish to diggest at a lower water temperature. When the water temparture drops below 9C then you should stop feeding completely till the Spring. 2) Remove any plant debris and leaves from your pond. Cover with a net to stop leaves from trees from falling