Very very interesting.....First time I get some sort of answer why mine changed colour. I am guessing, based on what you're saying is that it could be gene related. I also have one barb covered in gold specs, like gold dust that stays constantly, not due to a light reflection. It's visible no matter the angle. It was like that since it was a fry. Perhaps in my "clown loach wannabe" barb there's a 'xanthic gene also...that is not present in the other ones. And its interesting that the red stripe remains as red as ever, regardless of the other drastic colour changes.