Drain. Pour 1 quart white vinegar over drained fish; let stand 24 hours. Drain again; add sliced onions (2). Hat 3 cups white sugar and 4 cups white vinegar; cool. Add 1 cup white port wine and 1/4 cup pickling spice. Pour over fish and sliced onions and refrigerate. Can be used in 1 week. Keep sealed and in jars (glass).