I cannot find a great online image of a Saddled Parrotfish. I am identifying this fish via the book Reef Fish Identification by Paul Humann and Ned Deloach.
Scientific name:
sparisoma frondosum
Professional image:
https://www.fishbase.se/images/species/Spfro_m1.jpg
My images:
On approximately July 3, 2017 at: I took the following image:
Saddled Parrotfish are supposed to be in Brazil, Venezuela, St. Vincent, and Tobago. I took this image in Cozumel which is outside of this are but not so far outside that it is impossible.