Removing paint from back of tank

Hi all,

The back of my 220 gallon (2 metres long) came to me painted black. I'd like to remove it - and in fact have done a small area already - but don't want to freak out the inhabitants. The piece I have already done has been blocked out again with the white polystyrene that I use for insulation.

I cannot decide if it is best to do the whole lot in a day, or a section every few days. A section every few days would mean that the back would progressively go from totally black to completely white - and then I'd stick on the background that I actually intend to use, which is a 'rocks and branches' image.

Or perhaps I should do it at night, so when they wake up... surprise! :)

As always, your thoughts and experiences welcomed.

Catherine,
I would just do it all one day and be done with it, If it freaks them out they will settle back down again soon. They will get used to it what ever color it is. If they are skittish and you want to work on it, I would just move them to a bucket/s with an air stone and go to town on the tank. Then add them back.

HTH,
Al

Thank you Al, a sensible, straightforward answer that untangled my over-thinking of the job :)