Originally Posted by aryiman
Ok cause i thought some people used them to acclimate new fish before putting them in to the main tank.
Acclimate may not the the right word for it but you are indeed on the right track. Quarantining all new arrivals is one of the first best steps in preventing parasites et al from entering the main display tank.
size would really be dictated by the fish types introduced as NewinTown suggested but you can easily narrow that down by the display tanks size. The smaller the display, the less likely for larger fish and smaller QT
's will do. The larger the tank would mean the reverse.
If you have something along the lines of a 90 gal
or less, I would opt for a 20 gal
long. If the display is much larger, opt for a QT
more appropriate to that size.