This fish was photographed on November 11th off of Key Largo, Florida. Thoughts on what it is?
It's a Nassau Grouper, Epinephelus striatus. The odd coloration may have something to do with spawning.
Nassau Grouper with odd color in that the back half is so sharply contrasting. Though they can go from pale to barred to almost black I think it is an all body kind of thing. During spawning I think they do display a non aggressive bi-colored pattern with very faint bars. But I think this bi-color pattern is the upper half of the body darker than the "belly" half. But I'm no expert maybe this one has a special condition or maybe they can produce this pattern at will. ??
REEF Headquarters | P.O. Box 370246 | 98300 Overseas Hwy | Key Largo, FL 33037 | USA Phone: 305-852-0030 | Fax: 305-852-0301 | email: firstname.lastname@example.org