Who Gives A Fish Forums

HELP!
I've just added a stunning coflake beauty to the tank, and it's being bullied by one of the yellow tailed damsels. The rest of the gang - 4 chromis, hawk nose, maroon clown, yellow tang, and Banggai cardinal - seem fine, but this damsel's gone rogue. It's been chasing the beauty around the ...

It's got some characteristics of a mollusk, possibly a type of oyster or clam, but the soft sides and movement are throwing me off.