The arapaima gigas is the world’s largest fresh water fish. It can reach up to 15 feet in nature, and can weigh up to 440 pounds. In captivity they only grow to about 5 feet and need a very large aquarium to survive. The coloration of a pirarucu is a greenish head with the body a blue-greenish color. Near the tail the scales are reddish tint with a bright red edge. The arapaima has a very wide back and a sloping flat head with an overshot lower jaw. Their mouth faces upward, and they have long and low dorsal and anal fins, near the tail. They also have a bony tongue with a row of teeth they use to crush food up against the roof of their mouth. Dried arapaima tongues were once used as seed graters for soda drink powder.

 

The arapaimas are found in the Amazon and Orinoco River drainage of South America. During the dry season they seek the floodplain lakes with little oxygen so they can prey on the abundant fish trapped in a small area. Adults surface every 10-15 minutes but can stay beneath the water for up to 30 minutes. During the wet season the fish can be found throughout the flooded forest, in swamps, and up-stream in creeks.

 

Their niche is in calm water resting on the sandy bottom with submerged plants. They do well in their environment because the lack of oxygen makes the other fish sluggish and easy prey for the arapaima. They are also able to survive extensive drought periods by gulping air and burrowing in the mud or sand of the swamps. There are about 500 adults left. It is unusual to find adults larger than 4 feet. They are shrinking because fishermen are catching them for their meat. The meat is boneless and is 50% of their total body weight. The meat is a reddish color and tastes good.

 

Arapaimas eat other fish and even small birds from low hanging branches and are at the top of the food web. The fact that they can survive drought and still feed their selves when there is little food around is what helps them compete for food. Man is probably their biggest competition for food. The thing I thought was cool, about the arapaima gigas, is that it doesn’t chew its food it squeezes it with it’s tongue that has a tooth like bumps. Also, they use their beaks to dig pits that are 20” in diameter and 8” deep.

 

The female lays 50,000 eggs in those pits but then the male carries them in their mouth once they are hatched. Very few babies make it to adulthood. I think it’s important to find a way to help save the arapaima from extinction.

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Author: Joey F

Published: January, 2007

 

 Bibliography:

“The Virtual Museum of Natural History.” 25 January 2007 “Iwokrama a massive fish in danger.” 30 January 2007

“Arapaima.” 31 January 2007 “osteoglossidea” 31 January 2007 “Arapaima” 31 January 2007