Yep - Jolthead Porgy - I never in a thousand years would have guessed from the picture in the book, but reading the description and careful cross checking of body parameters (including size) confirmed the ID.
Book description indicates possible "striped or bloched pattern, especially when feeding". I wish these fish would lean to conform to the published pictures and keep their coloration consistant.
Since they probably won't maybe Humann/DeLoach could include variations of common coloration for all the fish instead of just some of them. There are so many immature/juvenile/location variations that they include. Why, in their infinite wisdom don't they include common variations of adults?
Anyway, thanks for the ID. Guess I'll have to go from body shape and not color first. This is the second time the book has baffled me.