The video shows a group of fish swimming around in a tank. The fish are of different sizes and colors, including yellow, green, and red. They are seen swimming in different directions, some near the surface while others are near the bottom of the tank. The tank is well-lit, and the water is clear, allowing for a good view of the fish. There are no visible plants or decorations in the tank, and the background is dark, focusing the viewer's attention on the fish.