A suggestion for lighting Sam...
...always leave flash off for photos and try shooting "down" on tank slightly for fullview photos...if you have the contrast adjustments on your camera it helps alot also...each elevation in photo angle will be a differnt setting to allow good light quality...
Digitals cant help but soak up the light , dont know why. Lighting tech's were the hardest thing to get used to with Digi.
Now Im battling with crisp "motion" shots...I tried asking the lil buggers to pose but they flipped me off ! :hehe:
Anyways ...try that bro...it might help.