Fish

Fish were animals of rivers, springs, lakes, and the Great Sea. Gollum loved to eat fish. He called them juicy sweet as he devoured them. Sam Gamgee referred to him as disgusting. He ate fish all through out the journey. Even when Faramir and his host of men captured them and wanted the One Ring, Gollum started eating a fish at the Forbidden Pool. Hobbits also loved fish, but it can be assumed that Gollum ate more fish than all of them combined.