Something fishy is happening in the Mekong River. More and more, people along the river are watching fish—dead fish—float by their houses. In Cambodia, kids row boats out into the water. In one village, they collect as many as 22 pounds of dead fish every day!

Because of drought, the Mekong’s waters are already low and fish are already dying. In 2010, Laos and Thailand started building the Xayaburi Dam on the river. That isn’t helping matters at all! River channels are going dry. Those channels lead to places where fish normally lay eggs or find food. Now fish can’t get to those places. If the new dams come in too, many fish species will disappear from the river. Some might even go extinct. That isn’t just bad for fish. It’s bad for people. Hundreds of thousands of people along the river rely on fish as a food source. The fish give them the protein, fat, and iron they need to live.

If the new dams are built, the river might also have to say goodbye to the endangered Irrawaddy dolphin. The Irrawaddy dolphin is a slow-moving creature. It looks a lot like the Beluga whale. Irrawaddy dolphins have big skulls, gray or blue skin, and long, broad flippers. They grow about seven or eight feet long. They are such a normal part of the Mekong River that they are also called Mekong dolphins. Loud explosions from dam construction harm their sensitive hearing. Fewer fish and fish eggs mean less food for the dolphins. Lately, people have tried hard to save the dying species. For a while, it looked like they might succeed. Will the new dams undo their work?