I know having 2 big tanks sounds cool! however, you should start with one and decorate according to the type of fish you want. Your wife will be more likely still want space for your other things also, unless you have a huge house? your talking about covering a room with tanks or at least two walls. My advice is to show her how much you love the one tank and can care for it and then she may like to get another smaller tank in a few months?