What's Killing My Fish

[fio1022]

I had a small-medium size Kole Tang that died recently and I would like to replace him..He appeared to be in excellent health and was eating nicely.He was a new addition and was only in the tank for about a week.About two weeks eariler I lost a Lemonpeal Angel that was also a new addition.It was purchased from a different LFS.
When I found the Kole Tang ,he was starting to be eaten by a Sallylightfoot crab.
Wondering what could have killed him.The only predeters in the tank would be a coral banded shrimp and a sally lightfoot crab.
All water parameters good and other fish are uneffected.(two yellow watchman gobies and two false perc.clowns)
I really don't want to see another fish die...
Any help is appreciated.Thanks

 

[thor32766]

thats a tough one could be many things. the crab isnt going to kill the fish. if your parameters are fine you might just have had bad luck on two fish. maybe someone else has a better idea

 

[onereefnotenuf]

was the fish acting strangely before it died?