You may want to get a larger tank than that. You can buy a 10g for under 10 dollars at any LFS (I got mine for less than that at *****). You also don't want to have large amounts of substrate in the bottom. At most you could have a cup or two of sand (not CC) from your display tank to help the cycle along. That said, a UGF would not work in this case. It's best to buy a hang-on filter (nothing fancy, mind you). Rocks will absorb medication if you ever were to medicate the tank. It's best to use a few pieces of PVC pipe instead because it won't absorb the medication yet it will still give the fish places to hide. Quarantine tanks don't need a clean up crew either. You could have one in there if you wanted, I suppose, but they would have to be transferred to your main tank in the event that a sick fish needed to be medicated or hyposalinity was to be performed. If the water from your display is good, you can use it in your QT. It'll help kick off the cycle along with the LS.
My 10g QT consists of a heater, powerhead, Whisper filter, a cup of sand on the bottom, a makeshift hood (to keep in the heat and prevent the firefish in there from jumping out), and a black tank background on three sides of the outside of the tank. The background is there to keep the fish from feeling too overwhelmed with his surroundings. It's also recommended to put this on the bottom of the tank (on the outside, of course) so the fish won't see his reflection. Often times, people will paint the outside of the tank instead of using a background.
-lefty
