The water of Hoan Kiem Lake has turned a strange colour in recent days due to the impact of a kind of poisonous algae.

The water of Hoan Kiem Lake has turned a strange colour in recent days

The water opposite to 25 Dinh Tien Hoang Street looked blue and some fish was found dead there. Vendors by the lake said that this phenomenon had appeared in recent days.

Prof. Dr. Duong Duc Tien, an algae expert, said that the phenomenon was due to poisonous Cyanobacteria algae.

This algae often breaks out at this time of the year. It also often appears whenever the lake is dredged. This kind of algae is quite poisonous to creatures in the lake, so authorities need to have measures to deal with the problem.

Cyanobacteria is very small so it is easy to drift ashore by light wind.

Fish found dead on the lake

Tien added that this algae needs to be carefully destroyed as if being thrown into the environment, it can be scattered away by wind and then develop again. It can also cause diarrhoea for people.

The cleanup of Hoan Kiem Lake which cost VND29 billion (USD1,318) was completed early February this year.