Drain the tomatoes into a sieve set over a bowl. Use the back of a ladle to mash and coarsely crush the tomatoes. Mix the coarsely crushed tomatoes into the tomato juice in the bowl.
Place the oil in a medium-sized pot over medium heat. Add the onion, garlic and jalapeño and cook until tender, about 3 to 4 minutes. Add the tomatoes, oregano, olives, capers and raisins and bring to a simmer. Simmer 10 minutes, or until the sauce is lightly thickened. Season with salt and pepper; remove from the heat.
Preheat oven to 425 degrees F. Spread 1/2 the sauce into a 9" x 13" baking dish. Cut the fish into 8 equal pieces and set on the sauce. Spoon the remaining sauce over the fish. Bake, uncovered, for 18 to 20 minutes, or until the fish is cooked through. Sprinkle with parsley and serve.