A banded coral shrimp is going to be a very opportunistic feeder. if it is possible for the CBS to catch and eat the cleaner than I fear that may be what happened. but on a lighter note. a cleaner shrimp will hide for a couple of days until he gets used to his tank. I would keep an eye out. I have 4 peppermint shrimp in my tank I have had them for over 5 months. I have not seen them for 4 months. I reaquascaped my tanks a few days ago and low and behold I found all 4 of them. shrimp for the most part are VERY reclusive animals. but the cleaner is probably the "bravest" of the shrimp I have kept. keep your fingers crossed and a sharp eye out.