Here's the deal:
Anyone who has kept two animals together and has a horror story - please share them.
Please do not regurgitate something you heard from a friend of your cousin's brother in law - or show the same old tired picture that pops up everytime this topic is raised.
If you do have a horror a story, state what you think you did wrong.
As Judy and I both have said, there are species that it won't work with.
The whole purpose of this post is not to encourage people new to the hobby to keep animals together, but to encourage people who don't have any direct experience cohabitating, to bite their tongues the next time they feel the need to bleat about what a no-no it is.