My QT tank is only 9 to 10 gallons and I want to put my fish in their for around a month. The reason is that I have noticed that my tangs have white spot

I assume that this has appeared when some new corals where added to the tank but unfortunately and my fault entirely where only in the quarantine tank for 3 weeks. It's just typical but thats life I suppose and I my plan is to ensure that the main display is cleared up rather than getting progressively worse.
So, the problem I have is that all of the fish will need to be removed and placed in the QT. Now I have 4 fish (two clowns and two tangs) the tangs are each around 3" in length and the clowns are around 2" in length. I am worried that the QT is too small or do you think that for a period of 4 to 6 weeks they will be ok?
The next problem of course is to catch them without taking apart the whole system! The fish always eat well so I may try a trap first.