Zoa looks to be eaten

[somewherebeyondthesea]

It's unlikely the shrimp is eating your zoas especially if it's getting food elsewhere (mine eats mysis shrimp) my shrimp also sways back and forth they do that in the wild too I've seen them do it while I was diving!

If you don't find what it is with the blue lights, I would suggest using a coral dip?