Perhaps we should make a sticky on how to take good pics of a tank
Anyway, some tips on taking good tank pics:
-Turn off all the lights in the room except the tank lights. If this is not possible, wait until it is dark. The idea is to shot the tank as the only bright object.
-Turn off your flash. Never use flash when taking a tank on action. You can never get a natural look that way.
-Avoid any excessive glares (this is including glares from the lights of your tank should any spills out to the room and not onto the tank).
-Avoid shaky ground when shooting. Get your best steady grip, make use of any object to hold the camera still. Armchair, table or a tripod certainly can help with sharpness.
-Know your camera and make use of its full potential. Learn the fuction like aperture and speed. Digicam usually has pre-set programs for our ease. Do some practise on different settings. If the camera got a light meter, it is even better and easier. Try adjusting light preset to fluoroscent if it can give you more natural colours.
-Shooting a whole tank, certain plants and fish are all different thing and requires certain individual settings and skills. Hone the skill and get more hands on experience.
-Last resort if everything that you have done at best does not satisfy you, is getting a better camera to play with (which is not a cheap option).