The video shows a group of fish swimming in a tank. The fish are of different sizes and colors, including a large brown fish with a long body and a smaller fish with a yellow and black body. The water is clear, and the fish are swimming around the tank, occasionally coming close to the camera. The tank appears to be well-maintained, with no visible debris or algae. The lighting in the tank highlights the colors of the fish, making them stand out against the dark background.