The Arapaima, also known as Pirarucu and Paiche, is one of the world’s largest freshwater fish, native to the Amazon river basin. This ancient, air-breathing giant can reach lengths of over six feet and weigh more than 200 pounds. Its unique ability to breathe air, using a modified swim bladder as a lung, allows it to thrive in the low-oxygen waters of Amazonian floodplains. The diverse array of food items it consumes reflects its immense size and specialized hunting adaptations.
Primary Aquatic Prey
The bulk of the adult Arapaima’s diet consists of aquatic life, primarily various species of fish and crustaceans. Its preferred feeding method is a powerful ambush, relying on a “gulper” strategy rather than a fast chase. The fish rapidly opens its large mouth, creating a sudden vacuum that sucks in nearby prey, which is then crushed by its bony tongue and teeth. This predator often targets slower-moving fish common in the seasonally flooded forests and lakes of the Amazon basin. The Arapaima’s ability to breathe air allows it to hunt effectively in low-oxygen waters where other gill-breathing fish are slowed down.
Terrestrial and Opportunistic Feeding
The Arapaima must surface for air every 10 to 20 minutes, making it a highly opportunistic surface feeder aware of its surroundings. This behavior allows it to target small terrestrial animals that venture too close to the water’s edge or rest on low-hanging branches. Using its massive, muscular body, the fish executes a sudden, explosive strike, leaping out of the water to snatch prey like small mammals, birds, and insects, including occasional primates and lizards. This feeding strategy is most pronounced during the wet season when the Amazon River floods, spreading the fish into forests where small vertebrates are more accessible. The consumption of floating fruits and seeds also occurs, demonstrating a flexible approach based on seasonal availability.
Developmental Dietary Shifts
The Arapaima’s diet undergoes a significant transition as it grows from a small fry to an adult. In their earliest larval stages, the fish primarily consume microscopic organisms like plankton. As they develop, they transition to a diet rich in small invertebrates and insect larvae. Zooplankton, such as cladocerans and copepods, are a primary food source for juveniles weighing up to about 500 grams. The juvenile stage then transitions to small fish and microcrustaceans before the diet shifts almost exclusively to larger aquatic animals, including fish, crabs, and prawns, once the fish reaches adult size.