But a new report says almost one-fifth of the known fishes in the Mekong, one of Asia's longest rivers, are threatened with extinction.

Though scientists say, it's not too late - if we change course now.

"I don't think it's too much to ask (decision makers) to find ways to develop the river sustainably and still maintain these incredibly productive and diverse fisheries that have supported people for thousands of years."

In the Mekong River lives a dazzling range of fish species.

Among them, the world's largest catfish, largest carp, as well as freshwater stingrays thought to weigh more than 1,100 pounds.

But a collaborative report, published on Monday by more than 20 conservation groups, issued a warning about the world's third most biodiverse river after the Amazon and Congo.

It says unsustainable development has put 74 fishes at risk of extinction.

With 18 species already critically endangered.

Zeb Hogan, a University of Nevada biologist, and head of the USAID-Wonders of the Mekong project, was part of the 'Mekong's Forgotten Fishes' report.

"There are new discoveries of freshwater species, fish species every year. So the Mekong River is still full of diversity, full of species that have yet to be described. So there's the potential as the basin is developed that we might lose species before they're even known to science."

Flowing through six countries from the Tibetan Plateau to the South China Sea, the river is also the world's largest inland fishery.

And a depletion of catches could threaten food security for some 40 million people across Southeast Asia, as well as China.

Among the causes, Hogan pinpoints the development of hydropower dams as the main culprit that fundamentally impacts the river system.

And he says, it's crucial that countries in the delta coordin ate efforts to reverse the damage done now - because the data show it's not too late to turn the tide.

"No species have gone extinct, the fisheries are still incredibly productive, and so what that tells us is if we take action, collectively take action to develop the river sustainably, there's still hope for the fisheries, the fish, and the people that depend on them."