above ground koi pond

So I'm setting up a new plywood pond in my garage I'm going to insulate it with a 2x4 brace. And then I'm going to plywood over that and probably put another thin sheet of insulation. Then the walls as well, I'm going to have so much scrap plywood by the dimensions of my pond I'm just going to...

So I live in Northeast Ohio where it gets pretty cold, typically it stays in the '30s but it can get in the teens. What are your thoughts about keeping above ground insulated plywood pond in my garage?

Okay so I just posted on another thread the possibility of using these nice 5/8" thick tempered glass panels a friend has offered me for free. Each pane is 6' x 4' and I'm aware I'd normally use thicker glass however if stress beams are used in the center between each panel and not one long...