Have white-eyed the body is laterally compressed, somewhat more elongated than in bream. The snout is thick, convex, the mouth is retractable, semi-inferior. The eyes are large (up to 30% of the length of the head) with a white-silvery iris.
The general color of the body is monochromatic, silvery, the back is somewhat darker. Extracted from the water, the white-eyed fish quickly loses its silvery hue, muscle elasticity, deforms, in no way resembling an agile, slender fish. Fins are grayish, unpaired with dark edges. The lower lobe of the caudal fin is elongated. The dorsal fin is short, with 3 simple and 8-9 branched rays. The anal fin is very long, there are 3 and 36-41 rays, respectively, which noticeably distinguishes the white-eyed from the bream. The lower lobe of the caudal fin is longer than the upper one.
It reaches an age of 7-8 years, a length of 41 cm and a weight of 800 g. In the Don, the average size is about 15 cm.The growth rates of the white-eyed are average: in the first years of life, the growth in length is the highest (about 5 cm per year), but already from the 5th year of life, they decrease, and although the weight gains at the same time increase significantly. At the age of 3, the white-eye weighs about 65 g, at the 4-year-old - 150 g, at the 5-year-old already more than 250 g. The branchial stamens are long, dense, 17-23 in number. The pharyngeal teeth are single-row (5-5). The scales are relatively large, with 48-52 (sometimes up to 54) scales in the lateral line. Vertebrae 45-48. Earlier, the South Caspian white-eye was isolated as a special subspecies, but now the allocation of subspecies is recognized as controversial.
White-eye is a typical river fish, forms a resident and semi-anadromous form. Prefers biotopes with fast and moderate currents, avoids floodplain water bodies. Adult white-eyed individuals always adhere to deep sections of the river and current; juveniles for some time stay in shallow waters near former spawning grounds. During feeding it keeps in small flocks, during spawning and wintering it gathers in large flocks. By autumn, they go downstream for wintering in deep pits, and in early spring they climb up the rivers to spawning grounds.
The white-eyed animal feeds on a variety of aquatic organisms. Its larvae and juveniles intensively consume small zooplankton, freely hovering in the water column; as they grow, their diet is supplemented by benthic invertebrates, such as the larvae of chironomid mosquitoes and other insects; at an older age, the white-eyed molluscs eat small bivalve mollusks, benthic amphipods, water donkeys. When foraging in the bottom layers, the white-eye often swallows a lot of sand with it, sometimes with an admixture of silt and detritus. In all periods of her life, the intensity of her nutrition remains generally low.
The white-eye becomes sexually mature at the age of 4-5 years with a body length of 18-22 cm and a weight of 100-200 g, while males usually mature a year earlier than females. It spawns in river beds, begins at a water temperature of 5-12 ° C, more often in the second half of April on floodplain rifts. White-eyed caviar is sticky, 2 mm. in diameter, larger than that of bream, it is usually swept out in the current onto stony ground. Its number in females of different age groups varies widely: for example, in several individuals from the Dnieper, 20 cm long and weighing about 150 g, the absolute fecundity ranged from 8 to 12.2 thousand eggs, in individuals 27 cm long and weighing about 500 g - from 18.5 to 20.9 thousand, the relative fecundity is about 30-80 eggs per gram of body weight. In the lower reaches of the Volga, after spawning, it slides into the desalinated areas of the Caspian. The hatched white-eyed larvae remain for some time on the bottom, the attachment organs, unlike many other relatives, do not develop in them.
The main habitats are confined to the rivers of the Black and Caspian Seas: the basins of the Danube (up to Vienna), Dniester, Prut, Bug, Dnieper, Don, Kuban, Volga, Kama, Vyatka, Urals. In the Volga, it was previously found up to its upper reaches (the Tvertsa River, Lake Seliger), but now it is rare here, if not completely lost, it is not found in the Moscow River. It is rare in the Kama River and its tributaries, but it is numerous in reservoirs. Common in the Kuibyshev, Saratov and Volgograd reservoirs.
In the Lower Volga, the white-eye is represented by a semi-anadromous form, lives mainly in the delta and delta of the Volga, does not go far into the sea. The South Caspian white-eye is common along the shores of the Middle and South Caspian. In addition to the main habitat, the white-eye is found in the Volkhov River and in the Volkhov Bay of Lake Ladoga. Occurs singly in the Vychegda and Northern Dvina rivers. It also exists in the Aral basin.
The economic value of this fish is not great due to its small number and limited distribution. In fishery catches, this species, as a rule, is taken into account together with blue bream and bream, or belongs to other commodity groups and to fines.
In the north of the range, in Karelia, the species is rare, its number is extremely small, lives only in the southern part of Lake Ladoga, therefore it is included in the Red Book of Karelia. The limiting factors here are the unfavorable temperature regime, typical for the northern border of the species range, and water pollution with industrial waste due to the progressive eutrophication of the southern part of Lake Ladoga.
White-eye is of some interest as an object of sport fishing. She rarely catches a bait, mainly after spawning. Its bite resembles the bite of a bream. It should be caught from the bottom, onto a worm, since it leads a purely bottom-up lifestyle. In the white-eyed fish, the meat is somewhat more tender than that of the blue bream, but very perishable. It can be eaten in any form: fried, boiled, salted, smoked, but best of all in dried (for several days the fish is kept in a saturated saline solution, washed and dried in the sun and wind).