It all depends of the fish, some are so ill that you dont want to do a dip right away, too much stress, so I get them in a copper tank and treat them with meds. When they begin to recover, I dip them, continue treatments.
OH, this was in your profile:
20 gallon Reef (Just set up)
-8 lbs live rock
-4 small hermits
-3 small sergeant majors
-3 very small and 1 small fish (silver with black stripe running
lengthwise and one running across top)
-and 1 very small pipefish (I think)
Ok, do you really think the pipe fish in a new tank with sergeant majors is a good idea? Hmmmmm......
Oh, and this is not a reef, its a fish and live rock tank.
Well, if you still have them, lets get you up on how to care for the tank.
What do you have for filters, and what are your day and night temps, are you using R.O. water? Do you have a test kit?
You really ought to think about retruning the Sargeant Majors, they are very agressive and will even attack divers. Slow it down a bit and lets get this thing going in a safe manner for the fish.