The Arapaima is a genus of very large fishes which dwell in the Amazon river basin. They appear in many episodes throughout the series.
This fish was featured in the first episode of Jungle Hooks made in 2002, where Jeremy Wade attempted to catch this fish on camera. After surmounting multiple frustrations, including near death in a plane crash, Jeremy finally used local techniques to bring in a 200-pound specimen.
In the episode Amazon Assassins in Season 1, Jeremy travels to the Amazon again in search of the 10-foot fish. He wanted to investigate what "spirit" had reportedly been smashing into local's canoes and eventually causing them to drown. In the end, he is rammed in the chest by an Arapaima, but it was not with full force. He catches a fully grown female fish in a nearby swamp.
In the special finale of River Monsters Season 4, Jeremy travels up the remote Essequibo River in Guyana. At the end of his journey, he reaches a remote lake, where he catches a large Arapaima.
In the premiere of Season 5, Jeremy suspects Arapaima are involved in the explaining the mysterious, hyper aggressive behavior of Piranhas in some regions of Bolivia. While Piranhas are famous for their ferocity, they will still typically avoid much larger animals such as humans in clear water. However, invasive populations of Arapaima in the regions seem to have led to extensive competition, forcing the behavioral change in the local Piranhas.
While investigating the Sobral Santos Disaster, Jeremy looks into Arapaima as a possible culprit. However, they are not as common in the main river channels as they are in shallow lakes. On top of that, they do not usually see humans as prey, but, rather, attack when they feel their offspring or themselves are threatened. Therefore, they could not possibly be responsible for killing hundreds of people struggling in the water.
Another account came from Guyana of a deadly mermaid that killed people without leaving anything behind. It allegedly "lured" its victims into the water where it killed them. Wade is then locked in battle with a huge 250-300 pounder, and because the locals made him use fly fishing, he is in deep trouble. Miraculously, he lands the fish, and it is the biggest of all of his South American monsters.
In the series finale of River Monsters, "Malaysian Lake Monster", Jeremy tracks stories of monster Arapaima allegedly on the loose in Malaysia. They were said to have been released as unwanted pets. However, Jeremy believes that the Arapaima is not a logical suspect for the two deaths on the lake. There are only two instances that Arapaima will attack. One is when they are cornered in nets, and another is when their nests are threatened. On Lake Kenyir, people do not net for Arapaima, and in order for a nest, at least one male and one female would have to have been released, and have been able to find each other somehow in the vast body of water. Jeremy felt like an Arapaima accident on Lake Kenyir would be a one-in-a-million freak accident.
In Mighty Rivers: The Amazon, Jeremy returned to South America to check the health of the mighty Amazon. Arapaima used to be commercially fished on a monumental scale, and he was surprised to find some left in the fish market. He found that a small area that was hunted responsibly was actually producing many of these giant fish.
The Arapaima is one of the largest freshwater fish in the world. An adult Arapaima can be 10 feet or more in length, and can weigh 440 lbs. A specimen 8 feet or more in length, can weigh 220 lbs or more. Specimens up to 6.5 feet in length are not uncommon. The largest one Jeremy caught was well over this size.
Some sources suggest that the Arapaima can grow to 15 feet in length, however, the weight provided by most of these sources is still 440 pounds. In his book, Jeremy estimated that a 15 foot Arapaima would weigh roughly 2000 pounds, meaning that these reports are probably inaccurate.
Arapaima generally live in shallower waters in muddy seasonal lakes and slow-flowing rivers. Their ability to breathe air ensures that they can reside in low-oxygen conditions that would kill most other fish. While the Piraiba is comparable in size to the Arapaima, their territories do not typically cross because of the Piraiba's tendancy to live in rocky pools, well away from the usual habitat of the Arapaima.
There are five currently named species existing in the genus Arapaima, however, the species most widely known is A. gigas. In Jeremy Wade's book River Monsters, he mentions that Arapaima gigas is now critically endangered, and some experts believe all currently caught specimens to be closely related species, and not A. gigas.
- This appears to be the report referenced in "Malaysian Lake Monster"