I have a 2 year old Kodak camera with a 10x optical zoom on it. If I could change one thing about it - which would make tank photography a whole lot easier - it would be having the option of turning off the auto focus. That's why most of us have trouble taking tank pics - the auto focus selects the glass as the focus point, instead of what's behind it.
Another feature you should check while shopping is the delay between the time you push the shutter button and the time the photo is actually taken. On my camera, it's about a second - which is a L-O-N-G time for a fish to swim out of the frame...
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