Bruce and Theo and others have kindly posted info on their systems for indoor fish raising. I've followed those threads with interest since I'm very much in need of a system for overwintering Tilapia.
Necessity sometimes leads in strange directions.
Here's my story. We had this old chicken coop, nice structure, but not much else. I needed a gym/workout area and so I've transformed the chicken coop into a very nice home gym. At the same time, we wanted to remove a spa/hot tub from the main house because it took up too much space and wasn't used any longer. I moved the spa into the newly created gym.
It looks to me to be perfect for overwintering Tilapia and any other fish. I'm going to hook up a 1500g pump to the spa to augment the filtration and to also provide the option of switching this unit back to a spa come springtime....if anyone decides to use it as a spa.
Only problem thus far is that because I went off to Mexico fishing and a cold snap came along, I lost all my Tilapia...before I could get them inside in the new accomodations....redneck aquaculture...making something useful out of something that isn't being used.
This may not be such a radical thought...in talking to the local spa store, they told me that they often get requests for spa removals(but they have never heard of anyone using an old spa for fish growing). People just sometimes get tired of them. Looks to me like a real potential for fish overwintering. Will post "the rest of the story" next spring.
New fish tank shown below with gym equipment in background:
