The algae is decreasing oxygen levels and disrupting the food chain.
A species of algae has invaded the Sword Lake in Hanoi, turning the water a strange green color.
Professor Duong Duc Tien said that climate change was behind the invasion, and that the blue-green algae needed to be removed.
Tien also said that it (cyanophyta) contained toxins that could harm other creatures in the lake. Some fish have gone belly up on recent days.
A representative from the Hanoi Drainage Company said that the rapid growth of algae and moss was draining oxygen from the water.
The company is working with Hanoi University of Science and Technology to transplant endemic algae to balance the environment.
At the end of 2017, Hanoi spent about VND30 billion ($1.3 million) on cleaning up the lake.
Source: Vnexpress