We always keep a giant bottle of fish sauce at home because we use it in many recipes. But if you don't have fish sauce, you can substitute 2-3 anchovy fillets (just for this recipe only). Add the anchovies the same time you add the garlic and saute it together. P.S. Here are a few other recipes using fish sauce, it's worth buying a bottle because you will use it up for sure: - Garlic and Fish Sauce Ong Choy - Garlic and Fish Sauce Eggplant - Thit Kho (Vietnamese Braised Pork and Eggs) - Pancit Bihon - Steamed Pork With Salted Fish - Cha Trung (Vietnamese Egg Meatloaf) - Yang Chow Fried Rice