Definitely lights. From my experience, the warmer light, 6000K to 12000K, tend to make acans go red & translucent. I have noticed that they prefer a cooler light temperature & do well under the 420nm to 460nm spectrum. Find an area with a bit of shade from your whiter lights at the bottom of your tank where your atinics dominate & can provide an up swept flow that can cradle the polyp. As always, check your parameters for anything that can set things off balance. Good luck.