I had a pair of neons. One died shortly after I got them. The other lasted almost 3 years. They don't have a long life span.
I had a chalk bass and I have seen them around but they never seemd big. I think that the royal gramma is a bigger fish with a bigger mouth and I didn't have problems with them either.
I can wait but the problem is a don't get out your way.
I had a breeding pair of chalks..they grew fast and the female could have eaten a gramma if she wanted to...LOL I had lots of damsels with them which they could have eaten, but the trick was to keep them well fed so they didn't want to work to chase their food down...