Oh gosh I hope my post didn't offend you! Not my intention at all! Most people would not KNOWINGLY buy a dyed fish. But I assure you, I would have when I re-entered the hobby of fishkeeping after over 25 years out of it, because when I last knew anything about fish, there was no such thing as dyed fish. Oh, I'd seen the "painted glass cats" but back then it was my understanding that was just some odd temporary paint job and a brief fad. I had no idea how things would progress in the matter of artificially coloring fish to the point of intentionally deceiving shoppers! It's something I never could have dreamed of...ever.
When I started shopping around again, half the time I didn't know what I was looking at, and if not for the internet, I would never have suspected some of the fish I was admiring in the LFS were dyed. I mean, it just never even occured to me such a thing was possible! Fish are either naturally colorful enough, or selectively bred to be very colorful...I was naive enough to be shocked that people could resort to something painful and inhumane just for cosmetic purposes? Weird.
Now I do have a few genetically altered day-glo Danios. I looked into how those were created and I didn't find anything about their creation that was against my own sense of ethics, though after talking more with other hobbyists, I do have a better sense of why a lot of people feel even this type of artificial manipulation is a bad thing.
Anyway, I just wanted to say my post was by no means accusatory. Even for the sake of argument say this was a dyed fish and you bought it just because you liked the appearance, trust me, I would be the LAST person who would condemn or even look down on you for it. My Clementine is an adored member of the family and we've had her barely over a week, yet can't imagine life without her. But I won't even post what she is because I know there are people who would ream me up one side and down the other or think a helluva a lot less of me for having her, without understanding or giving me a chance to explain why she came into my family. And since I don't feel obligated to explain myself to anybody I haven't got a face-to-face relationship with...just never mind what Clementine is!
Now back to your pretty but mysterious cory...you asked for opinions and based on the photo provided, it APPEARED like it could be a dyed cory. I don't dare put forth any OPINION expecting anyone here to take it as expert analysis because I'm far from expert. I have tried to educate myself a bit on the subject of dyed fish because it was such a shock to me to see dyed fish that I felt I should understand the practice and learn to recognize these fish to the best of my ability so I could avoid purchasing any. The article in the link that I provided indicated that the dyes used on cories are not unduly intense and in other photos I've seen the colors could possibly pass for natural, as there's a wide variation in how dyes look on individual fish.
Now as far as I know it's just the asian fish farms doing color alterations. If yours came in from SA, then it's possible it's a new unknown cory. But consider the odds of there being such a cory naturally colored like that in the wild, and compare the coloration against all photos of dyed cories you can find and let us know what you think.
It's my understanding that dyed fish can exhibit variations in the intensity of their coloring in reaction to stress or other situations. That may be what you're witnessing. I don't really know.
Tanks: SeaClear Acrylic 40 US gallons, Eheim Ecco 2236, Eheim Classic 2215, Fine gravel & EcoComplete: 3 Albino Aeneus, 4 Green Aeneus (NOT Brochis) 6 Peppers, 3 Sterba, 1 Elegans, 10 Danios, 3 panda cories, 1 cichlid.
5 gal betta tank: 1 male betta
50 gallon SeaClear Eheim 2213, Eheim 2215, fine gravel: 3 baby goldfish (2 Moors, 1 Oranda in QT)