Caspian Sea
The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, although it is not a freshwater lake. It contains about 3.5 times more water, by volume, than all five of North America's Great Lakes combined. The Caspian was once part of the Tethys Ocean, but became landlocked about 5.5 million years ago due to plate tectonics. The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it has no natural outflow other than by evaporation. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans.
Neogobius pallasi
Neogobius pallasi, the Caspian sand goby or the Caspian monkey goby, is a species of fish native to fresh and brackish waters of the Caspian Sea basin including the Volga drainage up to the vicinity of Moscow. It has been introduced into the Aral basin. This species of goby can reach a length of SL. It is also important to local commercial fisheries.