Hi Tony for your photo you are better off taking the shock in macro mode ( flower symble ) and do not zoom in on the tank just go closer to it with the camera. you may also be able to stand a few feet away in normal mode and take the photo You never want to use the ZOOM as this will use a smaller F Stop wich will make less light enter the lense there for making the shutter speed much slower and you won't capture a good shot unless on a tripod.

You want to use the largest Fstop lowest # your camera goes to (example F2.8) this will take the best shot with the least light needed and a fast shutter speed. you can use AV mode and select and set the F stop to the hiest setting (lowest # shown) and shut off the flash.

Also if your camera has a manual white balance setting place a light grey or white paper in the light you are going to be taking the photo of your tank in and use the manual white balance setting and set it up how they say most say push a button or take a photo of the white paper this will give you the correct balance setting and your photo should look much better for the light you are in.
SEE PHOTO this was taken with my panasonic point and shoot Lumix FS7 works pretty good for point and shootand it was on low Mega Pixel setting.
Hope this helps!
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