Scale the fish and trim the fins and tail. Leave the head on, but remove the eyes. To make the stuffing, melt the margarine in a pan, add the chopped onion and celery and fry gently for about 3 min. Add the rice and remaining ingredients and mix thoroughly over the heat for 2–3 min. Stuff fish with some of the mixture and spread the remainder over the bottom of a shallow fire-proof dish. Place the fish on top and cover with the bacon, cut in long thin strips, arranged in a criss-cross pattern. Bake in a fairly hot oven (375° F., Gas 5) for 30–40 min. (allowing 10 min. per lb.). Serve in the same dish, garnished with parsley or watercress.