I am always weary with large triggerfish as I have heard lots of tales of the titan triggerfish attacking swimmers and divers during nesting season. The yellowmargin triggerfish being about the same size as a titan, I would rather be cautious. This one came from the deep and swam towards the surface (and me) allowing me to take a picture.
Nikon D700, Nikon 28-105 mm macro at 105mm, F8, 1/60th, ISO 400, Ikelite Housing and Ikelite DS160 strobe set on TTL.
Marsa Shagra Bay, about 5 metres down, Marsa Alam, Egypt.