I have a small 15 gallon Rubbermaid tote housing some plants and white cloud mountain minnows. I was trying to find a way to insulate it to keep the temperatures up. I was thinking of building a frame using 2x4 and some unused wood flooring slightly bigger than the tub. Put Styrofoam in between the tub and frame and fill the gaps with spray foam. Finally a top with the corrugated greenhouse panel. Hopefully the greenhouse top can keep heat in from sunlight but if the temps drop too far down I will put a heater in. I'm not sure how effective that Styrofoam idea will be, any better ideas? I don't have the safety equipment for fiberglass. Also whats the lowest WCMM's can go? Seriously fish says 14 C or 57 F but I have seen some places that said they can survive 50 F.