Even if the fish was in its own holding cell at the LFS
, I would still quarantine it when I brought it home. Those single cells at the LFS
typically have water flowing through them from their entire system. However, if you do see the fish every couple days in its cell and it continues to look good for a month, I think that is way better than no QT at all.
I would wait a couple more weeks before adding another fish in order to give your good bacteria time to catch up with what fish you have in there already. Especially if you are reading between 0 and .1 you really need to be at a solid 0. This next thing I'm going to type is not recommended but it does work.... if you do add the other fish before a couple weeks then when you add the fish you should also add a bottle of bacteria in a bottle. There are a few brands of this but the brand I have used is called SuperBac and it does help.