Like others have said, if you need to use a flash.. you want one that is either
A.) Adjustable such that you can point it up or to the side so it bounces onto the fish.
or
B.) remote flashes that will trigger from a different location such that it wont bounce back into the camera.
basically, you want all your flash aimed to the fish.. not into a reflective surface and back at the camera =P
I find it better to cut the lights to the room you are in.. and then super beef up the tank lights to get awesome pictures.
A.) Adjustable such that you can point it up or to the side so it bounces onto the fish.
or
B.) remote flashes that will trigger from a different location such that it wont bounce back into the camera.
basically, you want all your flash aimed to the fish.. not into a reflective surface and back at the camera =P
I find it better to cut the lights to the room you are in.. and then super beef up the tank lights to get awesome pictures.