In retrospect to Lupin's well-made point, just because I don't always quarantine does not mean I'm not an "extreme" or "pro" hobbyist. I just spent 50 dollars on a single fish and you can bet your betta that it is in QT right now. We all do things differently, it doesn't make us pro or casual in any definitive sense.
What I don't understand is that people QT the expensive fish, but not the cheap ones... when it is the fish that are already in your main tank that you are protecting.
I do not have a quarantine tank. So I never quarantine. That being said I also only buy fish from one LFS whom I have never seen any poor conditions at. I have also never had a problem with the stock other than a batch of guppies that died. They were in with my Rams, and the Rams had no problem, so I believe it was just weak guppy stock. All of my water reading were the same as before they were added so nothing else was happening in the tank at the time.
What I don't understand is that people QT the expensive fish, but not the cheap ones... when it is the fish that are already in your main tank that you are protecting.
When I buy expensive fish it's usually ones that I've never kept before, so I always QT.
When it comes to purchasing a cheap fish, it usually means I have kept it before and I am confident that my knowledge of the fish, including common ailments in the species and the tank its going into are both satisfactory enough to proceed.
The price tag in my area just reflects the availability, and thus my experience with the fish. I didn't mean to imply that I QT a fish because said fish costed me a lot of money, it's all about the species.
I quarantine everything that goes into my tanks---fish, plants, and inverts. I do it to protect the fish I already have. Ich and flukes can hide in a fish's gills, and it can be weeks before it shows up as a full blown infestation in your tank.
I am guilty, though, of rushing the quarantine process and introducing fish to my main tanks too early. After the last investment in API General Cure to treat my 55 gallon tank and the 30 gallon, I hope I never do that again.
When this poll went up a couple days ago, I voted about half the time. For me, it depended on the store and the fish. When I did QT, it was usually only about a week to two weeks.
After this week, and having ich breakout in my 45 gallon and having my ember tetra dying off in my 20 gallon, all my new fish are getting QTed for two weeks, minimum, and probably longer.