Thanks for trying
I found another thread that suggested finding a clear, shallow bowl and rigging an edge around it - almost like a lid with a large hole in it but the lip would prevent them from coming out.

I am thinking about maybe a clear tupperware container and hot gluing the lid on, and making a large hole leaving about 1/2" all the way around and putting a rock in the middle, so that they can hop out.
If I do it, and it works, I will take pictures.