It might seem that the obvious answer to the title of this post is any room that contains fish tanks. Does that mean if you have tanks in multiple rooms that you have multiple fish rooms? Or is it a single room containing nothing but fish tanks, or only used for fish tanks?
Water on carpet. This is NOT a photo of my carpet in the basement. Photo from https://www.smartkilim.com/.
If you keep fish long enough, you will eventually experience a tank or filter failure that will inevitably leave you with a floor full of water. It WILL happen.
After nearly 20 years of personally avoiding such a disaster, my luck ran out this past weekend. I woke up Sunday morning and, like every other morning, went down to the basement where all but one of my show tanks are located. The basement is partially finished and partially carpeted.