Beer fish (pijiu yu) is the dish of Yangshuo — fresh river fish, usually grass carp or carp, braised in local Guilin beer with chilli peppers, garlic, tomato, and fermented black bean until the sauce reduces to a rich, slightly bitter glaze. It exists throughout Guangxi, but the version here uses fish pulled from the Li River that morning, and the local beer adds a sweetness that distinguishes it from the dish as made elsewhere.
The best beer fish restaurants are on the side streets off West Street and on Pantao Road, where the food is aimed at Chinese tourists rather than foreign visitors and the cooking is more reliable. Expect to pay 60 to 100 yuan for a whole fish serving two people. Point at the fish in the tank to select yours; the cook will return it to you in about 15 minutes. Order a cold Guilin beer to drink with it — the pairing is logical.