Fish compatibility/combination question

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Have a 6 line along with a Purple and Regal Tang, Foxface couple of damsels, 3 clowns and 3 chromis and never seen any signs of aggression toward the other fish.

Now not blaming the wrasse but considering the other fish, I can't seem to keep cleaner shrimp, peppermint shrimp or emerald crabs. All just seem to disappear after a while.