Canh chua is the quintessential dish representing the south of Vietnam, specifically the Mekong Delta. Fish would be caught in the delta and then brought home to make various main dishes. The carcass would not go to waste; the fish head, tail, and bones would make a stock. Canh chua usually contains chunks of fish, but the fish needs to have a tough, chewy texture, as catfish and monkfish do. It is traditional to serve the soup with the fish bones, tail, and head, but if you think that will be unappealing to your diners, simply remove these parts before serving. My great-aunt tells me that the best way to make this stock is with unsweetened pineapple juice to counter and balance the strong smell of the fish. A vegetarian version of this soup is canh chua chay (see recipe in the Vegetarian Dishes chapter), but it won’t have the same brininess and umami as a fish stock made from scratch.