Arrow crabs have been known to eat other inverts and small fish.
As far as the peppermint shrimp and camel back shrimp: they shouldn't eat corals if you feed them fresh fish every night, but who wants the stress of worrying all the time. Thats why mine are getting evicted tonight.
ps- advise is a verb, advice is a noun. not picking on you, it's just that I'm a nerd.