Everything that you put into the system affects the Bio-Load, Fish, Corals, Ect. They secrete waste so in turn you need a Bio-Load that can handle that waste. If you add to much to fast the bio-filter can not adjust its self that fast to compensate to the overload and will lead to your params being out of whack. You just have to make sure you do not add to many fish or corals to fast and give the Bio-filter time to catch up and stabilize. Yes he could add a fish in about 2 weeks I never said that he could not. But he just got the tank and yes it was an established system, but he moved it, so he has I am sure stirred things up and should wait for it to settle to add to many things to it...
He just moved the tank 2 days ago and has added 2 Tomato clown and 2 corals.. I am just advising him to take it slow, I dont not want to see him having issues...