The video shows a close-up of a fish tank with a variety of colorful corals and rocks. The corals are in different shapes and sizes, with some appearing to be brain corals and others resembling staghorn corals. The rocks are covered in algae and have a rough texture. The water is clear, and the lighting in the tank highlights the vibrant colors of the corals. There are no fish visible in the video, but the movement of the water suggests that the tank is well-maintained and the corals are healthy.