Ball Aquarium - Version 1.0 This interesting free online arcade game will test your reflexes and concentration to the maximum. You have to put all red balls in a red field and blue balls in a blue one. It is not as easy as it sounds. The balls are moving really fast. You have an adjustable slider with an open window through which balls can pass from one side to another. Move the slider up and down to pass the right balls to the right side.