A light blue rectangular tank is filled with numerous live crayfish submerged in clear water

A light blue rectangular tank is filled with numerous live crayfish submerged in clear water. The crayfish, exhibiting various shades of brown, olive-green, and reddish-brown, are densely packed across the visible surface of the tank. Several translucent plastic tubes, consistent with aeration lines, are distributed throughout the water, with noticeable air bubbles actively rising from at least two points, primarily in the central and lower-left regions of the frame. No human figures or other subjects are present. This scene is located in Rostov-on-Don, Russia.