The sterlet is a potamal freshwater fish that seldom occur in large lakes. It inhabits the lowland and foothill zones of the rivers and usually stays in the current in deep depression in the riverbed. Small specimens are often encountered in sandy shallows. The two kinds of spawning sites are the river bed at a depth from 7 to 15 m, and floodplain sites flooded by the rising spring water, on pebbles and rarely on gravelly-sand bottoms.It generally behaves as a resident fish.Does not undertake long migrations.Their main food in all rivers is benthic organisms, mainly insect larvae ( Trichoptera, Chironomidae, Ephemeroptera, Plecoptera, and Simuliidae ); small mollouscs (Sphaeridium spp., Pisidium spp. and Viviparus), annelids, other invertebrates , and also fish eggs, including those of other acipenserids, are also included in their diet. Young specimens feeds mainly on trichopteran and chironomid larvae. In the Volga river near its mouth, gammarids account for over 90 % of the food by weigh in young specimens. With increasing size, the role of tricopterans increases while that of chironomidae decreases.
Males reach sexual maturity at an age of 3-6 years old, one to two years earlier than the females. The spawning periodicity remains open: spawn every year or only after a pause (shorter for males than for females) of one or more years?. Possibly, in the northern part of the range, the onset of sexual maturity would be later, and a considerable proportion of the adult specimens would not reproduce during every spawning season (Sokolov & Vasilev, 1989). During the spring floods they do swim upstream in the river for spawning. Males appear at the spawning ground before females at the water temperature from 9 to 11 ºC. Females reach the spawning ground later, at a water temperature from 12 to 13 ºC. The optimal water temperature for the reproduction of sterlets ranges from 12 to 17 ºC. The sterlet has the shortest life span (22-24 years old) in the genus Acipenser and females live longer than males.
Maximum size 125 cm and a weight of 16 kg; usually below 100 cm and 6 to 6,5 kg.