In the video, a person is seen holding a glass container filled with gravel. The container is transparent and has a rectangular shape. The person is standing in front of a fish tank, which is filled with water and has green plants inside. The person tilts the container and pours the gravel into the fish tank, allowing the gravel to fall into the water. The gravel is small and round, and it creates a soft bed for the fish to swim on. The person continues to pour the gravel until the container is empty, and the fish tank is filled with the new gravel bed.