Looks like I started a good discussion. I've painted tanks in the past and was not happy with the results. In any case, for my existing tank, the tank is recessed in the wall and I can access the back and sides of the tank from a room behind the tank. I wanted to see what "temporary" (and perhaps less messy) options existed these days so I can still view the tank from the back by temporarily removing the background. I don't know if anyone has replied to my original question. Perhaps no one has taken that route using some kind of colored plastic or acrylic. I have however seen pictures of tanks on-line with it and it looks great, just not sure of what the exact material is and where to get it.
Here's another option...has anyone painted some kind of paneling or board (paper, wood or other material) and placed it behind the tank?
RC