Fiberglass tank w/window for outdoor pond

[ThorneZoo]

I have an existing pond, built years ago that's basically a wooden box with a pond liner in it. Measures 60x42 by about 3' deep. The problem is some new kids moved into the neighborhood now all they want to do is look in my pond and see the fish. These are small kids that aren't always watched by their parents and I'm not liking the liability it presents. So I need to move the pond to the back yard behind my fence. I was looking at a website that had a fiberglass tank with a viewing window. I thought that would be neat with some stone work added around the outside to make it look better than a blue box. Has anyone had any experience with these types of tanks? I plan to dig a partial base for it so it's level and make a stone patio around it. I need one that's at least 36" deep to accommodate my largest koi that is about 18-20" long. I don't want to get rid of the koi to have a smaller pond.