I have the following fish in my tank, and there seem to be some
casualties/attacks in it. What is doing this to them?

-2 x Three Spot Domino Damselfish
-2 x Three Stripe Damselfish (one of them is missing an eye this morning)
-2 x Blue Reef Chromis (one was killed two days ago, I saw the other Chromis
constantly attacking it's wounds before it eventually croacked. What
attacked it in the fist place?)
-1 x Fridmani Pseudochromis
-1 x Blue Tang
-a few red legged crabs
-snails

Thanks
Haig