South American fish in Southeast Asia

Alien species are found all over. From Vietnam:

"Some fishermen in District 2, HCM City on April 1 caught a strange fish of 60-70kg in a small branch of the Saigon River.
"The strange fish, which is over 1.6m long, has grey scales and red lines across its body, and a black and dark red tale.
"The giant fish was identified by experts as [Arapaima] gigas, which originated from the Amazon River in Brazil.
"This species of fish is considered the biggest fresh-water fish in the world. They eat smaller fishes and don’t harm the environment. With their nice bodies, this kind of fish is bred as ornamental fish.
"Fishermen sold the giant fish for VND40 million (US$2,500) to an ornamental fish breeder in Thu Thiem, HCM City on the same day."