The recent sightings of the Amazon sailfin catfish in Pakistan have sparked concern among environmental experts, who warn ...

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. Two new colorful ...

Measuring 10 feet (3 meters) long and weighing in at more than 400 pounds (180 kilograms), it's hard to imagine that the arapaima, the largest fish in the Amazon River basin, could ever go missing.

The Payara, often called the vampire fish, is one of the most aggressive predators in South American rivers. In this video, I ...

Piranhas are among the most deadly creatures in the water, with razor-sharp teeth capable of slicing flesh easily, but a fish in the Amazon River basin has developed a "bulletproof vest" to protect ...

Amazon basin fish species living in lakes, floodplain forests and river systems need a high degree of connectivity to stay genetically diverse and healthy, but this connectivity is threatened by ...

A freshwater Amazonian fish has evolved scales with microscopic armorlike structures specially designed to resist a piranha's piercing bite, new research shows. Arapaima gigas is the largest — and ...