I had an Arrow crab and Coral Banded live together fine for over two years in a 75 gallon. I had plenty of rockwork for them each to have their sides of the tank. I don't even think the Coral Banded even knew what the hell the Arrow Crab was
I have a coral banded and a cleaner and 2 peppermints in my 55 gal. And nothing is going on between them. They all have their sides of the tank and sometimes mingle, when I feed them, but nothing violent.
HTH