Very interesting post!
Thank you, glad you came to read the thread.
I knew that back in the beginning of the solar greenhouses, some had been built to have a cement water tank for passive heat storage and also grew fish in them, Tilipia [sp?] is popular for that.
I do not like fish that well, but do like good ideas.
Early on the first thread, I posted a different article on fish in a barrel.
There are several interesting posts on that site, altho I don’t agree with his other opinions, they are good articles that he found and posted.