If the fish are easy to remove from the main display you could put them back in there. It's not the best, but it will work. If the fish is showing signs of excessive stress in the bath, place it back int he tank. You can get a QT tank together really cheaply, though.
1. 10 gallon tank $10
2. Powerfilter $24 (I like the Aquaclear Mini) http://www.marinedepot.com/ps_ViewItem~idProduct~HG10595.html">http://www.marinedepot.com/ps_ViewItem~idProduct~HG10595.html</a>
3. Heater $14 [IMG]http://www.marinedepot.com/ps_ViewItem~SearchStr~Stealth%20heater~action~view~idProduct~HG10712~idCategory~FIHTGH~category~Hagen_Thermal_Compact_Preset_Heater__100_Watt__10_1_2_inch_Saltwater_Aquarium_Supplies_Heaters_Glass_Tube~vendor~.html">http://www.marinedepot.com/ps_ViewItem~SearchStr~Stealth%20heater~action~view~idProduct~HG10712~idCategory~FIHTGH~category~Hagen_Thermal_Compact_Preset_Heater__100_Watt__10_1_2_inch_Saltwater_Aquarium_Supplies_Heaters_Glass_Tube~vendor~.html</a>
4. A flowerpot for the fish to hide in.
You can get one together for around $50-$60. The best thing about using an aquaclear filter is that you can keep the sponge for it in your sump so you don't have to have the QT runing until you need it. Just pull the sponge from your sump for an instantly cycled filter that will turn the 10 gallon over 20x and hour. They're also easy to add other types of media if you need to pull a medication out of the QT tank.