What is the largest freshwater fish in the world?

Giant sturgeon fish reach enormous sizes in rivers, up to 3 meters long and 700 kg in weight.

One of the oldest families of bony fish in existence, the sturgeon lives in the rivers, lakes and shores of Eurasia and subtropical, temperate and subarctic North America.  They are distinguished by their elongated body, lack of scales, and large size: common sturgeons range from 7-12 feet (2-3 ½ m) in length, and some species grow up to 18 feet (5.5 m).  Most sturgeons are benthic, spawning in the headwaters and feeding in river deltas and estuaries.  While some live in fresh waters, very few enter the open ocean away from coastal areas.

Some sturgeons are harvested for their roe, which is turned into caviar (a type of delicacy) that makes some sturgeons the most expensive fish harvested.  Because they are slow growing and mature late in their life, they are more vulnerable to exploitation and other threats, including pollution and the marginalization of their habitats.  Most sturgeon species are at risk of extinction, which makes them more vulnerable to extinction than any other species.

Sturgeon is a freshwater fish that lives in North America, from Hudson Bay through the banks of the Mississippi River.  The slow-moving creatures, which prefer sandy or gravel habitats at the bottom of lakes or riverbeds, migrate uprivers during the breeding season.

The lifespan of a male sturgeon is 50-60 years, but a female can live up to 150 years.

The freshwater organisms are listed as threatened in 19 of the 20 states in which they are found, with over-harvesting and habitat loss among the causes of their decline.