Water quality is great, nitrate is 10, nitrite is 0, no ammonia, ph is 7.6.
It has been 3 wks now and they still won't eat. Three of them stay in one section of the tank and just "tread water" for hours. One has started scratching, but no signs of ich. Could it be flukes? Other symptoms - the top lip is white, and I never noticed this before. My local petshop owner said he sees red streaking. I see red just before the tail fins, but not really what I would call streaking.
I have coppersafe. Should I treat with that? How much do I dilute?
I've added 1Tbsp of salt for every 5 gal of water to prevent brown blood while we were going through the nitrite spike, which lasted about 4 days. I used Maracyn2 also, and the LPS owner recommended using it for a 2nd round, but I don't think it helped at all.
Please give me some advice. I don't want to lose these guys.

EDIT: I just realized one of my threadfin rainbows may have tiberculosis! I'm freaking out a little because my hands have been in and out of that tank fairly regularly. The only symptom is a curved spine right now. Should I quarantine? Could it be something else (I pray)?