The video shows a blue crayfish in an aquarium with a black gravel bottom. The crayfish is seen moving around the tank, and at one point, it climbs on top of a fish. The fish appears to be a white catfish, and it is lying on its side on the gravel. The crayfish then climbs back down and continues to move around the tank. The lighting in the tank is blue, and there are no other visible objects or creatures in the tank.