help with fish health

[fishforlife]

Well, my wife and I have had our first fish fatalities. We have two anthias that just up and died. One day they were eating, the one was hieding uder rocks and stoped eating. Eventually it turned very pale and died. there were no obvious defects, other than the pale skin. The other athias, did the sme thing. The rest of our fish are healthy and doing well. All of our water test are spot on and we do regualr water changes.

First anyone might know what they died from?

Second, what can I do to ensure good fish health?