They should be fine. But of course nothing is guaranteed in this hobby.Emerald are ok, right? I've thought about adding one to help with some GHA.
Both arrows and CBS are very mobile and have long arms so I think they are easier to attack each other. I just googled and of course some people have said they have had both in the same tank for years. Prob depends on size of each.
I just remember reading in tropical fish magazine many many years ago that they were natural enemies. I just don't remember which one was the bigger aggressor.




