replacing clowns

I remember reading a post of something like this a while back but now that
something has nabbed one of my clowns it's time for a replacement. I had
noticed that although they shared the tank one clown would protect his furry
mushrooms from the other so I assumed that they hadn't paired off so would
this make it easier to replace the lost one.
I have been told to have not more than two in the same tank as if they
paired off then they would kill off any rivals for their anemone. the same
person recommended adding a larger clown to ensure that it would have less
hassle.
opinions anyone?

Robin