A small Kaluga. Note its Goonch like mouth.
The Kaluga Sturgeon (Huso dauricus) is an extremely large and extremely endangered species of Sturgeon, closely related to the Beluga Sturgeon. It is from the family Acipenseridae and the genus Huso. This fish is really only found in the Amur River basin, but just like the Beluga, it spends pretty much half its life at seas.
Because this fish is capable of living in freshwater, it is considered a freshwater fish. It is also considered to be the largest freshwater fish in the world, because its maximum size is easily 6 meters in lengths, and well over 1100 pounds in weight. This fish will eat anything smaller than it, including smaller Kaluga's.
This fish is very endangered because of overfishing.