There was a discussion on this recently, I didnt chip in tho cos everything I do was pointed out, but here is a few tips Ive learned from taking mountains of crap pics:
If the camera has macro mode, use it. Its the little flower symbol. This allows you to take closeups without getting too blurred.
Dont use too much zoom, better to get about 10cm or closer from the glass with wide angle.
use the highest possible photo quality, then you can take photos as described above and crop them down to just the fish detail without losing too much quality.
Turn off room lights and if you use flash, angle the camera down or sideways fom the glass so the flash reflection isnt in the centre of your subject, if its to one side you can again crop it out.
Dont take a photo from below the tank bottom, with the camera pointing up, the tank lights will set the exposure too low to see any fish!
If your camera has burst mode or bracketing, use them as you are almost certain to get one good pic.
Use the focus and exposure lock, most digicams will hold the correct exposure and focus for a moving subject if you press the shutter half way down, then take your pic while following the fish with the target on the display, then wait for the fish to stop moving and fire!
Ken
