yea...this is because, if the dissolved oxygen in water is not enough, aro tend to breath more frequent to get oxygen, so in this case, the soft membrane at the gill plate will tend to curl...
bro...nice red.u shoud keep it...just starve the aro for few days and try to throw in som MP for it...by the way, i saw u have frons as tankmate, wonder what is the pH of ur tank??