I've got 2 questions. First is aesthetic, can I paint the back of my tank if I already have fish in it? Will any paint "bleed" through? Second, I've been slacking on my water changes, and my water is a bit mirky. It also looks like I have a ton of oxygen bubbles floating around. When I do the water change I'm sure it'll get rid of the cloudyness, but is there anything I should do to get rid of the oxygen?