T1 had one in with his but I THINK he got rid of it.
I have heard of them biting and even killing rays but I have also seen larger tanks with them in.
I expect if it is going to work you probably need 600+(ish)gals...or large footprint... and keep all concerned well fed, any less and you MAY need to make sure you have a quick way to separate them and a long term alternative solution.
For me the Rays are the No.1 priority so I would not add anything that could harm them, other people add Rays to a "monster community" where the Ray is not the number 1 focus for them.