Huay Xai is also a major fishing ground for the phla beuk, (Pangasianodon Gigas) or giant catfish - the biggest freshwater fish in the world (two-three meteres in length and weighing up to 300 kilograms). They are believed to swim all the way from the source of the Mekong, Qinghai Province in China. Although the phla beuk annual catch has dwindled in recent years, they can be seen during mid-April and May.