Eating the flood season

Mùa nước nổi — the season of rising water — is the annual spread of Mekong floodwater across the fields of the upper delta, mainly in An Giang and Dong Thap. It is a regular part of the year rather than an emergency, though high water combined with tides can still flood towns. The fish follow the water onto the fields, and the food of the season follows the fish.

Timing varies by place and year. SGGP writes that the cá linh season starts in the 7th lunar month — usually around August — and is richest once the flood is in. Vietnam Coracle describes flooding in the Tram Chim area as typically running from June to November, with September to December as the floating season. In practice, August to November is when flood-season dishes are most likely on menus.

Cá linh is a small, soft-boned river fish that arrives with the flood. SGGP lists the common ways to eat it: cá linh kho, braised; cá linh in a sour hotpot or in lẩu mắm; and cá linh lăn bột, fried in batter. To braise it well, cooks line a clay pot with split sugarcane and simmer the fish for three hours or more until the bones soften. It is also grilled on bamboo skewers.

Some of the catch is salted and fermented into mắm cá linh, a speciality of Chau Doc and Tinh Bien, which keeps the flood season in the kitchen for the rest of the year. Ask at a market which fish is fresh this week.

Lẩu mắm, the fermented-fish hotpot, is eaten all year but tastes of the flood fields. Znews describes the Can Tho and Dong Thap Muoi version as pork-bone stock with mắm from snakehead or linh fish, served with fish, shrimp, squid and pork belly, điên điển flowers and water-lily stems. In Long Xuyen the broth is made from mắm cá linh and served with điên điển, rau nhút and diếp cá. It is a group meal: the pot arrives with a large platter of greens, and everyone cooks their own.

Too early in the season — July, or a late year's August — you may find the dish names without the fish. During the highest tides, some roads and riverside eateries in the delta flood; check local news before travelling around the peak.

Freshwater fish should be eaten fully cooked. A 2014 study in Emerging Infectious Diseases found the liver fluke Opisthorchis viverrini endemic in parts of Vietnam, in fish often eaten raw or lightly cooked; the survey was in central Vietnam, not the delta, but the advice — cook freshwater fish thoroughly — applies everywhere. Braised, fried and hotpot cá linh are all cooked through.