I would heartily recommend Al Covo - my favorite in Venice. Great food, great hospitality, wonderful ambiance. Really cannot go wrong here. As you are there in October, pay attention to see if moeche (a crab from the Venetian lagoon that molts in spring and fall) are on the menu. Whether a main course or perhaps something to share at the table, it is quite good and something which you can not just only get in Venice but only if you are there at the right time.