Well, for me personally, it doesn't actually look like anything is wrong with her. Sometimes they just rest in that position, I have a baby that has a mild Swim Bladder problem that does that, she just floats up and takes on a slight 'S' curve to her.
She might be stressed, she will lose color when she's stressed so that could be the "discoloration" you're talking about. Is she in a sorority at all? If so that could be why she's missing some scales.
And from this view, I see no signs of Pop-eye which is great!
Can you get some pics of her side so we can see the scales you're talking about?