You shouldn't need anything special to place a five gallon tank on. Water is about 8lbs per gallon, so it'd be fair to assume your tank would max out at about 50lbs with gravel and decorations. Assuming that's about as heavy as a large stack of books, I think the bookshelf idea could still be carried out - especially if the tank is place on the sides of the unit where the supports are, not in the center. Otherwise, most other surfaces would work; an end table, coffee table, night stand, entertainment center, desk, you name it.
Last edited by Kittles; 08-03-2010 at 12:21 AM.