Arapaima Gigas

The arapaima (Arapaima gigas) is one of the world’s largest freshwater fish, native to the Amazon Basin, where it can grow over 3 meters long and weigh more than 200 kilograms.

Biologically distinctive, it is an obligate air-breather, possessing a highly vascularized swim bladder that functions like a lung, forcing it to surface every 10–20 minutes in warm, oxygen-poor waters.

Its body is covered in thick, mineralized scales reinforced with collagen fibers arranged in a layered, armor-like structure that resists piranha bites and has inspired biomimetic materials research.

Arapaima are apex predators, feeding primarily on fish, crustaceans, and occasionally birds near the water’s surface, and they play a significant ecological role in regulating aquatic food webs.

Culturally and economically important to Amazonian communities, the species has been heavily overfished in the past, but regulated community-based management has proven effective in restoring local populations.