We have had our RTBS for a little over two years and he/she is a little over 3.5 inches. I would say that they are peacfull to the other inhabitants, however mine do seem to enjoy playing 'tag' with some of the others who will play back, mainly my clown loach. ( he used to play all the time with my Blue Ram until his death) But have never witnessed any damage to him or others from chasing around.
Can be quite elusive at times enjoying hanging out under rocks or plants, but never to far away from any action going on. Out of all my current fish, I do belive his is one of my favorites.