Halocline or
thermocline, I'm not certain which one caused this phenomenon. In all four pictures, the EXIF data shows no difference, but the shots really look different. The fish, a Spotted Puffer, basically circled my position and I followed him around. The light changes, the background changes, and the way the light moves through the water *REALLY* changes.
On this trip, when it comes to Underwater Photography, I learned this:
Water *eats* light.
This trip was so fun, I took a zillion pictures, and I'll be posting more, soon.