Preheat oven to 230ºC .
Clean and gut fish, remove top and bottom fins, scale and remove gills. Stand fish up in a shallow casserole, just large enough to hold the fish. Pour wine over fish and add olives, jalapenos, tomato sauce, fennel and oregano. Drizzle fish with olive oil, place in oven and cook until just cooked through, about 20 to 25 minutes. Remove, sprinkle with fennel fronds and serve immediately.
(An excellent contorno for this dish would be tiny potatoes, roasted with garlic and rosemary.)