I believe this is a Lemon damsel - Pomacentrus moluccensis.

Camera:	Pentax Optio WPi
Date:	Wednesday, December 5th, 2007 at 6:31 AM
Exposure:	1/80 sec at f3.8
ISO:	80 asa
Lens:	Built In Zoom Lens at 11.9mm (equivalent field of view of a 71mm lens on a 35mm camera) With cropping (you see 30% of the image as shot), this lens is effectivly a 128mm lens on a 35mm camera
Photographer:	John Harvey
Scientific Name:	species related to Pomacentrus moluccensis (Lemon Damsel)
Tag:	underwater, fish
Larger Image:	1100 x 1467