Fillet fish and skin, remove the mudline, any fat from the meat and cut into bite size pieces. Mix 3 cups water to 1/2 cup pickling salt, place fish in the salt brine, refrigerate for 48 hours stirring a few times. Drain fish and cover with white vinegar, refrigerate for 48 hours stirring a few times. Prepare a brine using 1 cup vinegar, 3/4 cup sugar, one cup White Port wine and one tablespoon pickling spice. Simmer brine for 20 minutes and cool. Once brine is cool I add one cup wine, for each cup of wine in the brine recipe, to the cooled brine. Remove fish from the vinegar and place in a jar with layers of onion. Cover with brine. Age in the fridge for 7 - 10 days and enjoy. Fish will keep for several months in the fridge. I have done whitefish, walleye, northern and white bass with this recipe with good results. A friend uses this recipe and adds diced halepenos to the jar along with the onion. Cold water fish are better for pickling. Any bones in the fish will dissolve before eating. When I do 10 whitefish for pickling I need to use 5 times brine mix ratio to get enough to cover the fish. I get Fairbank White Port wine in the 1.5 L bottle. When mixing the salt and water for the salt brine be sure to make plenty to cover the fish well.