In the video, we see a large fish swimming in a tank of water. The fish is brown and has a long tail. It is swimming around the tank, occasionally coming up to the surface of the water. The water is clear, and we can see the bottom of the tank, which is covered in green algae. The fish seems to be healthy and active, and there are no other fish or objects in the tank. The lighting in the tank is bright, and we can see the fish's movements clearly.