The video shows a group of fish swimming in a tank. The fish are of different sizes and colors, with some being larger and having darker colors, while others are smaller and lighter in color. The tank appears to be made of glass, and the water is clear, allowing for a good view of the fish. The fish are swimming around, sometimes coming close to the glass, and at other times, swimming away. The lighting in the tank is bright, highlighting the fish and their movements.