Tolstolobik

the Russian common name for two genera of fish of the family Cyprinidae, each including a single species: the silver carp (Hypophthalmichthys molitrix), which weighs 20–25 kg, and the bighead carp (Aristichthys nobilis), which weighs 30–35 kg. The bighead carp is distinguished from the silver carp by its larger head, darker coloring, and shorter intestinal tract. The natural area of distribution of both is China and the southeastern part of the USSR (the Amur basin). Both fish feed on plankton—the silver carp on phytoplankton, and the bighead on phytoplankton and Zooplankton. The reproduction period is in spring and early summer; the eggs are natant.

The carp are important for commercial fishing and fish breeding and have been widely acclimatized in warm bodies of water north to approximately 55° N lat. In the USSR they account for approximately one-fourth of all fish raised in ponds. They have been imported to Indochina, Japan, Cuba, and the USA, as well as to Rumania, Bulgaria, the German Democratic Republic, and other countries of Europe. In the USSR they inhabit the basins of the Aral Sea, the Black Sea, the Sea of Azov, the Caspian Sea, and Lake Balkhash. A method of gathering the young in ponds has been developed.