: Mix species!!! as long as they are doing fine. Plus I was asking about the vivarium. Those guys aren't in it.
And to quote him, use a blender, it gives them a nice, quick death instead of a slow one. Some can appear fine, but eventually something happens. Believe me, I had an Oregon and red-spotted newt in together for several months, and then all of a sudden during feeding the Oregon decided to chew on the red-spotteds head. I'm sure if you look around you can find other horror stories about mixing.