"The arapaima, found in South America, has an elongated body and a head so bony that the male fish will sometimes kill each other with a nifty headbutt. It's believed to be the biggest freshwater fish in the world."
South America
"The arapaima, found in South America, has an elongated body and a head so bony that the male fish will sometimes kill each other with a nifty headbutt. It's believed to be the biggest freshwater fish in the world."