Marvel Iron Man Background 29g 19.25x31.5in. Bring the heroic world of the Marvel universe to your aquarium with this officially licensed Marvel® Iron Man Background. Designed specifically for 29-gallon tanks, this vibrant aquarium background features the iconic Iron Man, adding an exciting comic book theme to your underwater world. The background measures 19.25" x 31.5", making it a perfect fit for a variety of aquariums. It's a simple and effective way to hide wires and equipment while creating a stunning new backdrop that enhances your fish tank's appearance.