The video shows a fish swimming in a tank. The fish is seen swimming around the tank, and at one point, it approaches a filter. The fish appears to be a medium-sized, dark-colored fish with a lighter underbelly. The tank is well-lit, and the water is clear. The fish moves smoothly and gracefully through the water, occasionally turning and twisting its body. The filter is white and cylindrical, and it is attached to the side of the tank. The fish seems to be curious about the filter and approaches it several times. Overall, the video captures the peaceful and serene movements of the fish in its aquatic environment.