Unknown shrimp (No pic.)

[Gools]

I just bought a millipora, and right now it's in a bucket getting acclimated. But I put the flashlight on it and I saw a small lime green shrimp, picking away at the coral, in a cleaning manner. There is also a acro crab on it. Anyone know what that shrimp is? Sorry don't have a camera. It's about the size, of the frozen PE mysis shrimp. Any imput would be appreciated. Thanks