Giant Stingray: These fish can grow to 16 feet and 1,200 pounds. It’s believed to lurk on muddy river bottoms of Thailand, Indonesia and Malaysia. In the Amazon, they’re known as “wish-you-were-dead fish” because of their painful sting. When it stings you, it gets a barb which can be up to 8 inches long, in your flesh that injects a painful poison.