The invention discloses a cup. The cup is composed of a control module, a waterproof conducting wire, simulated fishes, LED lamps, a cup outer wall, a switch button, a handle, a cup inner wall and a storage battery. The cup is characterized by being mainly composed of the cup outer wall, the cup inner wall and the handle, wherein a gap is kept between the cup inner wall and the cup outer wall, the cup inner wall and the cup outer wall form a closed space, the gap is filled with oily liquid, a plurality of simulated fishes are placed in the oily liquid, the LED lamps are arranged on the simulated fishes, the control module is arranged at the middle part of the bottom of the outer side of the cup inner wall, the simulated fishes are connected with the control module by virtue of the waterproof conducting wire, the storage battery is arranged at the bottom of the cup outer wall, the handle is arranged at the right side of the cup outer wall, and the switch button is arranged at the upper part of the handle. When the cup is used, a user only needs to pour water into the cup, and the user presses down the switch button to cause the LED lamps to emit light when hoping to enjoy the sight of the cup. The cup disclosed by the invention has the beneficial effects of simple design, low cost, reliability, durability and strong practicability.