Ok, so anything else I should watch for? I have about 18 days left in QT...
Is this your first fish? If so I'd honestly consider prophelatic treatment for ich with copper and flukes with prazipro. That's just my opinion but I'll explain why:
I quarantined every fish I got and ended up getting flukes in my tank (specifically on my chromis). I've never even heard of flukes before I started researching about them and supposedly they're really common. My chromis hasn't died of the flukes and seems healthy but every now and then will absolutely spaz out and shaking/twitching his head.
I'm ranting a little sorry...so your original question:
You should watch out for twitching and shaking of the head as if their trying to shake something off them (as I explained before that's probably flukes)
Ich look for white spots. Lethargy, not eating are other things to look out for.
Usually if a fish is active and eating it's healthy.
HOWEVER, a seemingly healthy fish can still have a parasite and bring it into your display tank, which is why on my future tank i will be prophelatically treating all fish. At the end of the day though I believe if your tank has enough space for the fish and the water quality is in check, even if there is ich or something in there, your fish will be okay.
Okay so I totally rambled on that but I hope I answered your question. I just thought I would share my own personal experiences with quarantining.
