Coral banded can be mean. Sometimes they will kill cleaner shrimp if they can catch them. Mine did. My coral banded even tries to catch my fish but he hasn't had any luck at that yet. They will eat whatever they can catch.
How big is your tank? I have a coral banded in my 24g with a few peppermints and they're fine. They can get pretty nasty though, I've heard numerous horror stories. Mine stays perched upside down in his cave, he only comes out when I feed. However, if my clowns go near his cave, he does snap at them (they're too quick though.) He also nipped at my YWG once when he went near his cave, and he got a piece of his fin (This was an isolated incident though, the goby has since recovered and stays away from the CB's cave.)
My tank is a 220 gallon. I saw it with my own eyes. Research it online. I did the other day and it even says they will kill other shrimp and they are opportunistic hunters. My Coral banded is huge too! He's molted about 5 times in 6 months. I love him. I wouldn't take him out of my tank unless I caught him red-handed catching someone and eating him.
My coral banded killed 4 of my cleaner and peppermint shrimp and tries to catch fish occasionally. He is cool to look at but I would get him out if I could catch him.