In the Asian family of popular sauces, the flavor of oyster sauce is somewhere between fish sauce and soy sauce, as it is made with oysters, as well as sugar, MSG, caramel color, and wheat. Both are thick sauces with a syrupy texture and deep brown color, and both are widely used in Asian cooking. It might be a little fishy tasting for some palates, more of an acquired taste. Hoisin sauce does not have fish sauce (although you can add it if desired).