Known locally as ruoc song (river shrimp), the tiny crustaceans are commonly found in brackish waters along river estuaries in Haiphong City and Hung Yen and Ninh Binh provinces.
The shrimp are harvested from muddy tidal flats when the water recedes, marking the start of the annual fishing season for local residents. Though small in size, the species has long been prized as a local speciality.
Unlike larger shrimp and prawns, river shrimp are only about the size of grains of sand and are typically dark grey, brown or pinkish-brown in colour. Mature shrimp tend to be darker, while younger ones are lighter in colour.
"Many visitors seeing them for the first time mistake them for sand or mud," said Nguyen Viet Quoc, a resident of Tay Thuy Anh Commune in Hung Yen Province.
"They are abundant in brackish estuary areas. Fishermen have to use very fine-mesh nets to catch them," he said.
The shrimp are usually caught using funnel-shaped nets made from thin but durable fabric. The nets are secured with bamboo poles in shallow waters, allowing the shrimp to drift in with the current before being collected.
Depending on the area, the shrimp may vary slightly in colour but generally have a mild fishy smell. During the harvest season, prices typically range from VND 70,000 to VND 90,000 (USD 2.7-3.4) per kilogramme.
In Tay Thuy Anh, locals often braise the shrimp with male jackfruit flowers, creating one of the area's best-known dishes
Locals also stir-fry the shrimp with wild betel leaves, creating a simple dish that highlights their natural sweetness.
Once cooked, the shrimp lose their fishy smell and turn an attractive reddish-brown colour while retaining a rich, savoury flavour.
"It's a perfect dish with rice. A single plate can easily disappear with several bowls of rice," Quoc said.
In Haiphong, home cooks prepare the shrimp in various ways, including roasting and braising, though the most popular version is river shrimp cooked in tomato sauce and served with fresh herbs.
Preparing the shrimp requires patience. They are placed in cloth bags and repeatedly washed in water to remove mud and impurities until the water runs clear.
The cleaned shrimp are then cooked with tomatoes, ginger and sour ingredients such as starfruit or tamarind before being seasoned with herbs.
Many first-time diners are initially hesitant because of the shrimp's unusual appearance. However, most are surprised by their sweet, distinctive flavour after tasting them.
For communities living near river estuaries, river shrimp are more than just a seasonal food. They are closely tied to childhood memories and generations of traditional fishing practices.
From a tiny creature often mistaken for sand, local residents have created dishes that capture the flavours of their homeland and remain a distinctive part of the region's culinary heritage.
