yep dark room - room lights off, pull curtains etc turn telly off too. i use flash as it brings up more colours in the fish but using the flash you get that reflection to avoid the reflection angle the camera slightly and take a few test photos to check that the reflection isnt showing. (note: it helps to use a tripod when doing this) then you have to get lucky waiting for the right fish to swim by :lol:
quite often when you see a few good photos what you dont see are the other 100 photos that were taken as well just to get the 3 or 4 good ones