Yes. Get your qt as close as possible to the params of the fw dip tank/bucket (78-82 degrees, 0 ammonia/nitrite/nitrate, 8-12dKH, 8.0-9.5pH, etc.), then do the dip and move them to qt for a while. Your display tank will need to be fish-less for a few months before you can re-introduce them.
That said, if it's not bad and they're your only three fish, you can attempt to deal with it in the display. Feed your fish a lot of good, garlic- and vitamin-enriched foods, shorten your light cycle, and do anything you can to avoid stressing them.