Split the catfish. Heat a dry heavy skillet until very hot. Lay the catfish, skin side down in the hot skillet. Leave it until the fish can be lifted out, leaving the skin adhering to the skillet. Cut the salt pork or bacon into small pieces and fry it until brown and crisp in a large iron pot or deep skillet. Lift out the pieces of fried meat with a slotted spoon and discard or save for cracklings. Add the chopped onions to the drippings and sauté them until tender. Add the tomato soup, water, catsup, salt, cayenne and Worcestershire sauce. Bring the mixture to a boil, taste and correct the seasonings. Lay the catfish on the sauce. The catfish can be cut into bite sized pieces if desired. Cover the pot, and simmer for 20 to 30 minutes or until the fish separates from the bones. Do not stir it, but occasionally lift the pot from the heat and whirl it to prevent sticking or scorching. Once the fish is done, move it to a hot platter. If the sauce is thin, cook it rapidly for a few minutes to reduce it. Pour the sauce over the fish and serve. Serves 6