A fisherman netted a four-ton whale shark off the coast of Bac Lieu province in the Mekong Delta Thursday night.
The fish gradually became weaker and finally died, fisherman Nguyen Van Sang said, adding that it became trapped in their net while they were fishing some 23 nautical miles from the coast.
The fish, which is six meters long, was taken ashore Friday.
Bui Van Thong, deputy chief of Lang ong Nam Hai (Whales' temple), said the fish, which is worshipped as a deity by Vietnamese fishermen, will be buried at the temple.
It was the third whale shark to be caught in local fishermen's net in the provincial Ganh Hao Estuary this year.
The largest living fish species, whale shark is labeled vulnerable by the International Union for Conservation of Nature and its current population is still unknown to world scientists.