The Tac stream is the largest stream of the Muong Tac-Phu Yen region, running through many communes before pouring into the Da River. The river criss-crosses the Muong Tac rice fields and several kinds of fish caught in the stream are used to make Pa nam Tac. 70 year-old Dinh Van Mo of Phu Yen district told VOV: "I used to go with my dad to catch fish from the stream when I was small. I remember the stream was always full of fish. Now I only go fishing when the river water level is high. Sometimes I can catch up to 3 kg of fish a day."

The fish is stuffed with local vegetables, herbs, and seasonings then wrapped in banana leaves before being grilled over a wood fire for 50 minutes. Nguyen Thi Hong Phuong from Hanoi said: "I was very impressed with the grilled fish. It was very rich, tasty and really subtle, especially when eaten with steamed sticky rice and a special salt by the Thai."

Measures have been taken to protect the water quality and maintain the fish population in the Tac stream. Dinh Thi Ngan, head of Phu Yeu district’s Culture Division, said: "To maintain the fish population, we’ve encouraged the local people to use fishing nets and fishing rods instead of electrical shocks to catch fish in the Tac stream."