Your cc star is not part of a cuc its a carnivore. It probably ate your shrimp. Now iam not saying it killed it, but it def would eat it. Brittle stars are more of a cuc.
Do u have any power heads?
Just curious if I'am alone here lol. When feeding alage sheets to my fish, my file fish and saddle puffer also ate it. Not a nip and go either , full on meal time lol
I have a clown goby. When feeding you definitely know its there. Otherwise its hit or miss. Mainly bc there color just lends them to be camouflaged. Nice fish tho