In winter, the role of wintering riverbed depressions is reduced to the usual wintering of various fish species. In this regard, currently relevant questions are: functioning of riverbed depressions in the period of open water, relationship of fish in the predator-prey system, and dependence of horizontal and vertical distribution of fish of different families in river areas and their value. The aim of this work was to reveal the patterns of vertical and horizontal distribution of fish in the wintering riverbed depression on the Irtysh river in the period of open water. We conducted a research during the summer period (June 23, 2015) in the Gornoslinkinskaya wintering riverbed depression situated on the Irtysh river in the territory of Uvatsky district, Tyumen region, 58°43'35,58''N, 68°41'45,75''E. The maximum depth is more than 41 m. To determine the average density of fish and their number, we performed hydroacoustic surveys by the ''PanCor'' complex, which is based on the sonar ''Furuno'', analog-digital converter and GPS-location. On the investigated water area, we used a boat to move along a grid of tacks (zigzagging). We processed the hydroacoustic survey files in the laboratory using special applications: ''PanCor'', ''Taxonomy''. For analysis, the water column was conventionally divided into 4 horizons: surface-pelagic (<10 m), 2 pelagic (10-20, 20-30 m) and bottom-pelagic (> 30 m). To analyze the correlations of fish distribution of different taxonomic groups, the nonparametric method, Spearman rank correlation, was used. The degree of statistical significance of differences in the distribution of fish in the different horizons of the water column was carried out using the sign test. In the distribution of representatives of percidae and coregonidae, which were represented only by predatory fish species in the area of our research, we found regularity: their proportion increased with depth for percidae from 15.07 to 35.89%, for coregonidae from 4.6 to 9.26% from the surface to horizons of 20-30 m; at the depth of more than 30 m the proportion of corigonidae remained about the same - 8.09% (See Figure 1). Cyprinidae dominated throughout the entire water column of the investigated water area, in terms of numbers: at the depth of less than 10 m - 77.64%, 10-20 m -64.70%, 20-30 m - 59.77%, at the depth of more than 30 m, their proportion was the lowest - 51.31% (See Figure 1). From cyprinidae in all horizons of the water column, juvenile fish with body length up to 15 cm dominated. From the surface to the bottom, the proportion of these fish in the layers of water was decreasing. For percidae, the maximum distribution values for the majority of the size groups of fish characterized the 1-st pelagic layer. The distribution of coregonidae and not identified fish was similar to that of percidae. The distribution of fish is determined by the dominance of juvenile cyprinidae in the surface-pelagic horizon, and fish of other families, predominantly carnivorous, in the 1-st pelagic layer, which is the window of ''anti-predation'' in the watercourse - a strategy of defensive behavior and survival (See Figure 2). In the vertical aspect, a significant correlation (high and moderate) is revealed between individuals of the same family and representatives of predators and prey in the conjugated horizons of the water column, reflecting the mechanism of proportional distribution of some species and simultaneous reduction of their intra - and interspecific competition, as well as trophic behavior, which is also noted in the horizontal aspect - in fish of different families. (See Tables 1, 2). The article contains 2 Figures, 2 Tables and 36 References.