What are good fish to add to established tank

I like the Chalk Bass, too. A very attractive fish, but unfortunately
they are not readily available in my area. So, I think I'll go with a
pair of Percula's.
I have a small hospital tank set-up which I keep around in case of
emergencies (such as disease outbreaks, etc.), so that I can treat any
sick fish without endangering my inverts and live rock. I'm going to
use this as my quarantine tank. Thanks for the suggestions.
Angel