That's interesting, none of my greys ever moved away from it, but Atlas seemed to have a burn like mark on his head last spring after getting new UV bulbs. (Before that, he was in QT with just an incandescent on the tank.) I thought it was from an incandescent that I used to heat, but even removing that, the mark was still there. When I switched to LED, it finally healed up. Made me wonder if the UV was too strong for the size of tank and the greys. None of my other 3 ever had an issue like that, but Atlas slept as close as possible to the lights, where the other 3 kept a bit of distance from them.