1 3/4 cups White Wine
1/2 cup Lime Juice, freshly squeezed
1 1/2 tsp Mustard Powder
1 medium Red Onion, sliced 1/4" thick
1/2 cup Olive Oil
Salt & Pepper, to taste
Combine all ingredients in a glass bowl. Cover, and refrigerate over night to allow flavors to meld. Then add fish to the bowl, covering all sides with the marinade, and then recover and allow to marinate for at least 3 to 4 hours in the refrigerator.