I know...not very fishy, but blame that on the subject, the crop, and the lens axis being true to the earth.
Morning Glow Pentax K-3, KMZ MC Zenitar 16/2.8 Fisheye
Mesa Arch is located in Canyonlands National Park, near Moab, Utah. Due to its only being a short hike from the road, it is one of the more frequently photographed features there and is a frequent subject for calendars and the sort. The strong glow on the underside of the arch seems to be due to reflected light from red rock surfaces on the cliff below. The glow disappears when the sun is not low in the east.
Steve