The video shows a close-up of a Betta fish, also known as a Siamese fighting fish, swimming in a tank. The fish has a vibrant blue and white coloration, with a large, flowing tail and fins that are spread out in a fan-like shape. The fish moves gracefully through the water, occasionally changing direction and showcasing its beautiful colors and patterns. The tank appears to be well-maintained, with clear water and no visible debris or other fish. The focus remains solely on the Betta fish throughout the video.