Coral Banded Shrip, additional shrimp?

Was wondering if I could add perhaps a different type of shrimp to my system without the Coral Banded going pyscho. I'd like to add maybe a scarlet cleaner shrimp but wasnt sure if this would be safe or not. I have a 55Gal tank thats been up for about 3 months. Fish as follows

Sixline Wrasse
Royal Gramma
Percula Clown

2 Emerald Crabs, 10 or so turbo snails, 15 mix of scarlet and blue hermit crabs. 2 black and grey brittle stars. Any suggestions would be appreciated.

Hmm well thats good information, i figured maybe if i got one that was bigger then the current coral banded. He pretty much hides in a cave all day and only comes out at feeding time and when the lights are off. Not a very exciting animal, nice looking though.