Web cam behind tank?

Has anyone had any success with a web cam showing decent visibility through glass? In my 150DD I have a paired shrimp goby and pistol shrimp and they are so fascinating to watch. My problem is they chose the back corner and are blocked by the overflow so I can't see them without playing a game of solo twister. The back is not painted so I had a thought of trying to rig up some kind of web cam back there.





If that is a no-go does anyone have any advice on how to encourage these guys to "relocate"?