Subject: What 3 liquids can I use to make a liquid wire?

I am an artist. I want to light a low voltage light bulb suspended in the middle
of a fish tank with no visible mechanical connection to a power source. I need 3
liquids a high density conductor, a medium density insulator and a low density
conductor that will not mix. Ideal liquids will be clear, cheep (starving
artist), and stable for a month or longer (the length of most art shows). The
light bulb will float in the insulator and wires will extend up and down to the
conductive layers. If the light bulb works I want to operate a small electric
motor in the middle layer so low viscosity for the insulating layer would be a
definite plus. I am thinking water or salt water for the dense conductor and
mineral oil for the insulator. I need a low density conductor for the top layer
or a new combination of liquids.
Thanks for your help 

Re: What 3 liquids can I use to make a liquid wire?