Aggressive Fish

[houndhome1]

I have a well established tank with a variety of fish who all seem to get along ok. Yesterday, I put in a Heniochus and he was instantly attacked by my Dwarf Angel! Then, my Yellow Tang went after him!!!!!! I have this poor new comer in an isolation tank now...what can I do about this? What causes this type of aggression on the "new guy"?
:needhelp:

 

[nicetry]

Established angels and tangs are extremely territorial, and as such, are best added last. Your heni will continue to be the brunt of aggression. A couple things you could do would be to rearrange the rock work in the tank, turn off the lights sand then introduce the heni. Option B would be to remove the tang and angel, introduce the heni and then replace the other two in a few days.
What size tank are these fish in?

 

[angelsrock]

if you have these fish in a 75 gallon, that would be your problem.