cut into 2-inch chunks (northern pike or crappies recommended)
Mix 1 cup water and salt to make salt brine. Soak fish pieces in brine for 24 hours.
Drain fish and soak for an additional 24 hours in vinegar.
Combine sugar, pickling spice (in spice bag), vinegar, remaining 1-1/2 cups water, and port.
Simmer for 10 minutes and cool.
Place fish pieces and onion in a crock.
Pour wine sauce over and weigh fish down with plate.
Let stand 1–2 weeks.
Place in jars and store in refrigerator.