Trumpetfish often hide in soft corals hanging head down. They are actually well camouflaged, but in a photograph due to the strobe light (flash) their smooth skin reflects the light making them more visible. Trumpetfish do vary in size but are generally about 18-20 inches long. See also Trumpetfish and a Fish Trap and Under a Table Coral.
This image is available to 7 x 10 inches.