So I might be able to get a 100 gallon stock tank to go on the side of my house and I was wondering how to keep it warm or from freezing in winter. I’m planning on stocking it with my Chinese Hi Fin Banded Shark, as well as my Longnose Gar, and maybe even other things like Goldfish, Koi, Shiners, Darters, etc. The measurements are 56” L, 36” W, and 20” H. Besides finding something to cover it, how else can I protect it from freezing? Several heaters? Water flow?