Rinse fish fillet and pat dry. Season polenta with salt and pepper to taste. Dip fish into polenta, making sure both sides are well coated. Heat olive oil in a medium-sized skillet on medium-high heat. Add fish and saute for 5 minutes. Turn and saute another 5 minutes for a 1-inch thick fillet.
Meanwhile, heat olive oil in a medium size pan. Add onion and garlic, salt and pepper and saute for 3 minutes. Add eggplant and zucchini and continue sauteeing for another 3 minutes. Stir in tomato sauce, and water and bring to a simmer over medium-high heat. Lower heat and cover. Simmer for 15 minutes. Vegetables should be cooked through but a little firm.