In dispersing seeds, the pirapitinga plays an essential role in the survival of the Amazon forest. When the flood season arrives, it becomes primarily frugivorous, and focuses its eating activity on seeds and nuts from the plants and trees growing in the flooded forest.
An important part of the seeds ingested manages to survive the pirapitinga’s chewing and digestion. Moreover, some of them are so hard that they can’t germinate without experiencing the action of the fish’s digestive juices.
These seeds are sometimes released kilometers away from the spot where they were consumed. Scientists have already identified, in a pirapitinga’s stomach, seeds from 27 trees and 26 different herbaceous plants.
The pirapitinga is resistant and adapts to the changing conditions of the environment and the seasons. It can, for example, withstand a lack of oxygen in the water during the dry season. It will stay close to the surface in that case, where there’s a higher concentration of dissolved oxygen.
This fish is able to hear underwater. It possesses an organ called the “Weberian apparatus,” a complex bony structure connecting the swim bladder and the internal ear. Additionally it can release chemical alarm signals capable of informing other pirapitingas of danger.
The pirapitinga also has a lateral line, like all other fish. This is a subcutaneous organ that enables it to swim in a school without colliding with other fish.
Large pirapitingas have become very rare around certain big cities in the Amazon like Manaus (Brazil) and Iquitos (Peru) because of the intensive fishing carried out there to supply public markets.