Cape Malay Pickled Fish

Name: Cape Malay Pickled Fish
Ingredients: 1/3 cup vegetable oil; 4 large onions, halved and thickly sliced; 3 tablespoons mild curry powder; 1 teaspoon turmeric; 1 teaspoon paprika; 1 teaspoon ground coriander; 1 tablespoon whole allspice; 1/2 cup turbinado sugar; 1 tablespoon peeled, finely chopped fresh ginger; 1 tablespoon finely chopped chiles, seeds removed; 3 dried bay leaves, thinly sliced; 2 teaspoons sea salt; 2 cups white-wine vinegar; 4 1/4 pounds Arctic char fillets, bones removed and cut into 5-ounce pieces; 3 fresh bay or lemon leaves