The video shows a yellow fish swimming in an aquarium. The fish is bright yellow in color and has a sleek body shape. It is swimming near a rock formation in the aquarium, which has a dark color and rough texture. The fish moves gracefully through the water, occasionally changing direction. The aquarium appears to be well-maintained, with clear water and no visible debris. The lighting in the aquarium highlights the vibrant color of the fish and the contrasting dark rock formation.