Volga undermouth

The Volga undermouth or Volga nase (Chondrostoma variabile) is a species of freshwater ray-finned fish belonging to the family Leuciscidae. This species is found in the Emba, Ural, and Volga drainages of the Caspian Sea basin and the Don River drainage of the Black Sea basin.

Volga undermouth
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Leuciscidae
Subfamily:	Leuciscinae
Genus:	Chondrostoma
Species:	C. variabile
Binomial name
Chondrostoma variabile Yakovlev, 1870

It is a riverine fish but is also found in reservoirs. The distribution is in lowland areas and foothills, and the fish prefer river stretches with strong currents, including rapids. Larvae and juveniles have a superior mouth, but at 3–4 months, they change to adult feeding mode (undermouth) and start grazing the bottom, eating benthic diatoms and detritus from the hard substrate. Breeding females deposit sticky eggs on gravel bottoms in shallow parts of rivers with moderate to strong currents.