Bend the body of the fish in a circle, pour over it half a pint of vinegar, season with pepper and salt, and let it stand an hour in a cool place. Then pour off the vinegar, and put the fish into a steamer over boiling water, and steam twenty minutes, or longer for large fish. When the meat easily separates from the bone it is done. Drain well, and serve on a napkin placed on the platter, decorating with sprigs of curled parsley.