5 Facts About the Arapaima

The arapaima or pirarucu is the largest freshwater fish in the world. Here are a few facts that you might not have known about this massive amazon fish. As always, we start each article with the video we made about it:

The Arapaima Facts Background

I spent two summers in the amazon looking for wildlife. I had hopes of seeing a wild arapaima but every time we went out to find one, all we’d ever come back with were Piranha. And as a side note, that’s why I wrote the article about how to survive a piranha attack. In the end I had to go to the Universeum on Gothenburg Sweden to actually see some of the arapaima in their massive freshwater tank.

So, let’s get to a few of the more fun facts about the largest freshwater fish.

1 – Arapaima breath air

These fish live in the murky waters of the amazon and have a modified swim bladder that serves as a type of lung. This means they swallow air from the surface and then use that to absorb the oxygen with. They can use their gills, but not much.

2 – Arapaima are among the largest freshwater fish in the world

The arapaima can grow up to 15′ long and weigh up to 440 lbs. Because of that is considered by most people to be among the largest fish along with the beluga sturgeon, mekong giant catfish, giant freshwater stingray and alligator gar. In some ways, it depends how you measure “largest” but these are some of the biggest in the world.

3 – They are Mouth brooders

There are a bunch of other fish that are mouth brooders – meaning they take in the young and protect them in their mouth until the fish get a bit older.

4 – Arapaima have gastrointestinal tracks that are opposite every other fish

This is an odd science fact but most fish have gastrointestinal tracks that go to the left of the stomach. In some ways, that’s just weird because every other fish that’s not an osteoglossiform fish, have intestines that go to the right of the stomach.

5 – Arapaima are going extinct

Extremely sad, but the arapaima is going extinct. According to this study, they are already extinct in 19 percent of their range and unless people limit their fishing of these massive fish, their continued existence is questionable.

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Written by Rob Nelson

Rob is an ecologist from the University of Hawaii. He is the co-creator and director of Untamed Science. His goal is to create videos and content that are entertaining, accurate, and educational. When he's not making science content, he races whitewater kayaks and works on Stone Age Man.

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