I purchased an Olympus C-5050z about 2 weeks ago. This is a 5mp didigtal camera. My aquarium shots have not been impressive due to my harsh lighting (10k 65W CF right on top of the glass). I plan to move the light higher. This camera has every bell and whistle that you could imagine. I bought the camera for underwater photography.
Here are some samples:
I know that this isnt an aquarium, but its still a good picture. :P