Heat oil in large nonstick skillet over medium heat. Add onion; sauté 5 minutes. Add tomatoes; sauté 3 minutes. Stir in zucchini, corn, 3 tablespoons basil and parsley. Cover and simmer until zucchini is crisp-tender, about 3 minutes.
Add halibut fillets to sauce in skillet. Sprinkle fish and sauce generously with salt and pepper. Cover; simmer until fish is opaque in center, about 5 minutes. Remove from heat. Drizzle lime juice over.
Using spatula, transfer fish to plates. Spoon sauce over. Sprinkle with remaining 2 tablespoons basil and serve.
Per Serving: calories, 320; total fat, 8 g; saturated fat, 1 g; cholesterol, 54 mg. Nutritional analysis provided by Bon Appétit See Nutrition Data's analysis of this recipe ›