1. Pickle the fish: Heat oil in a large skillet over medium-low heat. Add onions and cook, stirring, until soft and translucent, about 20 minutes. Add curry powder, turmeric, paprika, and coriander; cook, stirring, until fragrant, about 1 minute. Add allspice, turbinado sugar, ginger, chiles, dried bay leaves, and salt; cook, stirring, for 2 minutes.

2. Carefully add vinegar and 1 cup water; increase heat to high and bring to a boil. Reduce heat to a simmer and cook pickling mixture for 10 minutes. Remove from heat and pour some of the pickling mixture into a 12-inch glass dish. Add an even layer of fish and pour over a little more of the pickling mixture. Add another layer of fish and repeat process until all the fish and pickling mixture have been used. Top with fresh bay or lemon leaves; loosely cover and let cool completely. Cover tightly and transfer dish to refrigerator; refrigerate for 2 days.

3. Fry the fish: Remove fish from pickle, reserving onions, and pat dry. Place flour in a shallow dish and set aside. Heat oil in a large nonstick skillet over medium-high heat. Dredge fish in flour, shaking off excess. Add fish to skillet and cook, turning once, until golden brown and cooked through, about 4 minutes per side. Transfer fish to a paper towel-lined plate to cool.

4. Serve: Meanwhile, place raisins in a small bowl and add enough water to cover; set aside. Fill a large bowl with 4 cups water; add salt and stir to combine. Add cabbage, apples, and celery; let stand 20 minutes.

5. Drain raisins and cabbage mixture and add both to a large bowl along with parsley, mint, and cilantro; toss to combine. Serve fish topped with reserved pickled onions and cabbage mixture; garnish with cilantro leaves.