Fin Friends 29 or 55 Gallon Aqarium Divider with Suction Cups (29 or 55 Gallon) 12.5" X 18.75" Please Measure Your Tank Before Purchasing. 29 OR 55 gallon fish tank divider. Approx 12.5in x 18.75in. Please measure your tank before purchasing to make sure these dimensions will fit your tank. If your tank is wider than 12.5in or shorter than 18.75in then this divider will not fit. Suction cups that attach divider on top and bottom of aquarium Pins that hold mesh and side/top rails together Seperates aggressive fish, breeding fish or fry Seperates fish without extra filteration or heaters needed