One of the largest freshwater fish in the world is the Giant Freshwater Stingray. Its poison is most like that of a Rattlesnake.
Unknown to science until 1990, the Giant Freshwater Stingray, sometimes called a whip ray, is a relatively unknown animal that lives in freshwater rivers and lakes in Southeast Asia.
These ancient fish haven’t changed much while existing over many millions of years. They can reach 5 meters (16.5 feet) long and weigh up to 600 kilograms (1,320 pounds). It is unknown how old this species gets and if they ever enter the ocean during their lifetime.
Though stingrays are not aggressive, they are one of the few megafishes that can pose a real danger to those who handle them. Each ray holds a deadly barb on the base of its tail that can easily penetrate human skin and even bone, much like a hunting arrow. This stinger can be as long as 38 centimeters (15 inches) and holds a toxin with enzymes that cause tissue death.
The barb has two components: the sharp inner barb used for piercing, and a thin sheath surrounding it that contains the venom.
The gooey venom was found to me most like the one of the pit viper rattlesnake, strictly neurotoxic with virtually no local signs of swelling and inflammation around the sting. Just severe pain in the area that no victim can ever completely recall or compare. The poison causes skin and muscular tissue to melt away locally around the sting.
The snake’s venom consists of 90% water and has a minimum of 10 enzymes and 3 to 12 nonenzymatic proteins and peptides in any individual.
In Asia Giant Freshwater Stingray are seriously threatened by overfishing and habitat destruction. The fishing tourism has made it a challenge to catch these giants who normally fight for several hours on end when on the hook. Large stingrays have been known to pull boats upstream and even underwater.