Though arapaimas can stay underwater for 10 to 20 minutes, they tend to remain near the water's surface, where they hunt and emerge often to breathe with a distinctive coughing noise. They survive mainly on fish but are known to occasionally grab birds close to the water's surface.
The arapaima's proximity to the water's surface make it vulnerable to human predators, who can easily target them with harpoons. Some indigenous communities consume the arapaima's meat and tongue and collect its large scales, which are fashioned into jewelry and other items.
The Amazon's seasonal floods have become part of the arapaima's reproductive cycle. During low-water months (February to April) arapaimas construct bottom nests and females lay eggs. Young begin to hatch as rising water levels provide them with flood conditions in which to flourish. Adult males play an unusual reproductive role by incubating tens of thousands of eggs in their mouths, guarding them aggressively and moving them when necessary.
While this giant fish's habitat is relatively unmolested, overfishing has become a serious problem, and some South American authorities have attempted to enact protections."