A big blue fish with an also big yellow spot

A Surgeon fish. Oval body. Crescent like tail fin. Small orange fin near the tail is the sharp surgeon knife.
Arabian Surgeon fish

Arabian angel fish

( Pomacanthus maculosus )

Arabian or Yellowbar Angelfish lives in Red Sea only. It's a big blue fish with an also big yellow spot. Size 50 cm. Compare it's size with a yellow butterfly near it.