50% water change will knock half off those numbers, you need to get that Ammonia out now, or your just stressing out the fish, and there would be no reason to have them in there. With those numbers, I'd do a 75% WC tomorrow, and 50% every day until those numbers are gone. How long has the QT been up and running? Is it cycled? Or are we talking about just adding to many fish at one time to a tank?