Great idea but if it is larger than 4x4 it won't fit into my building... Outside the sides need to be higher... My German Shepherds LOVE water and have 2 pools like this that they play in all spring and summer long. I could do it if I bought some fencing material to go around it though...

So the bubble wrap floats on the surface?
I wonder if I could use Styrofoam??? Or do the fish try to eat the stuff?