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 arapaima or pirarucu, native to the Amazon. (Jeff Kubina via Wikipedia [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]) (CN) – The design of the ...

Arapaima gigas is a big fish in a bigger river full of piranhas, but that doesn't mean it's an easy meal. The freshwater giant has evolved armor-like scales that can deform, but do not tear or crack, ...

A new type of giant Amazonian fish — one for which only a single species was known for more than a century — has been discovered in Brazil, scientists say. The fish is a new species of arapaima, which ...