The Caspian kutum (Rutilus kutum) or Caspian white fish is a member of the family Cyprinidae from brackish water habitats of the Caspian Sea and from its freshwater tributaries. It is typically a medium-sized fish, reaching 45–55 cm in length, rarely 70 cm, and weighing up to 4.00 kg, rarely 5.00 kg.

Beneath the surface of the Caspian Sea are an array of fish species, including the Caspian sturgeon, whose roe yields the coveted delicacy known as caviar. Other inhabitants include the Caspian seal, the only aquatic mammal native to the sea, and the Caspian gull and Caspian tern, which find sanctuary along the shores.

The Caspian Sea’s abundant fish species are a cornerstone of its fishing industry. The diversity of species, including sturgeon, kilka, and Caspian salmon, provides a range of valuable resources. Sturgeon and Caviar: Sturgeon, renowned for their prized caviar, are a highly sought-after species in the Caspian Sea.

Salmo ciscaucasicus, the Caspian salmon or Terek trout, is a salmonid fish endemic to the Caspian Sea and its inflowing rivers.