Are you using a tripod? If not, try and do a test with and without using one, you'll see a huge difference in image quality, pumps off, clean the glass on the inside of the tank really good, try and not aim down thru the glass, keep the camera lens and glass parallel. Might have to postion the coral in the tank so that you can stage the shot. If the camera doesn't have a connection for a tripod, use the timer feature and rest the camera on stable surface.