[Andrew]

clean the glass, turn the flash off, try and set your camera to manual then set the aperture to the smallest number available, then set shutter speed to around 1/50 use a tripod or a pile of books, align the tank in the viewfinder then use the self portrait timer-this will eliminate camera shake, its hit and miss with the fish but these settings should start you off, experiment.

 

[Andrew]

this is a macro feature. Its a close focusing system in the computer chip, most slr lenses have the ability to focus closley, but a dedicated macro lens will give great results, thats what i use to take photographs of oxygen bubbles and plant details.