Nice first attempt. It looks to be a little hot around the forehead. Try to get the subject when it is off to the side of the flash and not directly under it. It will reduce blow outs and also help to light up the underside of the fish.
more practice tomorrow then! im really getting into it now . ive been looking through your pics on your website , your aquatic shots are simply incredible. id like to try and have mine end up that good 1 day. altho i have a long way to go yet!