i had the base made with a footprint of 36'' x 52'' it holds a 24'' water level, i have a rescue rtc (only 5'')that will be comfy in there for a while ,, i have started getting the kit together for an indoor pond to transfer him to later in the year ,then when the tank becomes free again i am going to research what would be comfy in there to have 10 or 15 off,,