The video shows a large group of fish swimming in a circular formation underwater. The fish are dark in color and appear to be moving in unison. The water is clear, and the light from above is shining through, creating a beautiful and mesmerizing effect. The fish are of various sizes, but all seem to be of the same species. The circular formation they are swimming in is quite large, and the fish move in a synchronized manner, creating a hypnotic and captivating display.