If you are looking for a good all around point and shoot I have been very happy with the Canon A series cameras. They do well when photgraphing an aquarium, show correct colors, have manual white balance adjustments and easy to use manual focus when needed. I found the AF to work well and quickly. Only drawback to using it as a point and shoot is it is bulkier than some other cameras which fit in your pocket much better.
I also have two sony cybershots, they are great when I want to have a camera with me and the guys at the bar or something, but don't have a manual white balance and the macro feature is not as good as the canon. so not so great for aquarium photos.