SRI Happie Shop Aquarium Underwater Glowing Effect Multicolour Jelly Fish (Big, 7 Inch In Length) Randam colour available colours - blue, orange light green ; pink. Its not battery operated. Its simple imitation of jelly fish in different colors. Its is kept in the fish tank as an additional attraction and decoration. Its moves as the waters makes movement in your fish tank. Its glowing effect only. There is a facility to fix it in the bottom of the tank and the toy jelly fish erects up in the water and moves as your fish tank water is moved and slashed by the fishes, aeration from your air pump or water flow from top filter.