Heat oil in large nonstick skillet over medium heat. Add onion; saute 5 minutes. Add tomatoes; saute 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.