Triggers and most other fish are prone to ich. I have read that wrasses (fairy) don't get ich so easily because of the "cocoon" they produce while sleeping but I am unsure of this being a known fact. If ich is your main concern then I would recommend setting up a quarantine tank for your new additions and old since they are being held at your lfs. You never know what is in their system. Best advice anyone can tell you is when in doubt, do as much research as possible.