I have a 40 gallon breeder tank cycling right now and am not sure if I want to set up a quarantine tank or not. I have access to a 20 gallon high tank but don't want to put much money into the tank at all. Any suggestions for a cheap setup? Also say I make a quarantine tank, a fish should stay in there for about a month, feeding it regularly. What should I be looking for when the fish is in the tank? What are the red flags?