In the region of Ha Long there are many varieties of shell-fish, such as flat shell-fish, conches and giant clams. Each variety should be cooked differently, and has its own particular taste. One of the more popular dishes is ốc đĩa browned in chilli sauce.

The ốc đĩa is a small flat shell-fish (đĩa means plate in Vietnamese). It is cleaned, placed in a pot without water and then boiled in chilli sauce. It is cooked without fat, and only with a sprinkling of sliced lemon. It is often eaten with some Diếp Cá or basil leaves, and usually as a side-dish with some beer.