Description on Tesco direct reads:-
The I-Fish robotic toy has the ability to swims and swishes to the beat of music. I-Fish can also acts as a speaker for your music player. This robotic toy responds to any sound source. Plug into a personal music system or place near a sound source to activate I-Fish lights and sounds. I-Fish is suitable for 8 year olds and over.
May be of some use to somone out there!!