So I have a few fish in my 30 gallon QT tank. 2 small clowns, sixline, blenny, and my kole tang. My 180 gallon reef is going fallow which I'm almost done with! I've had the kole for about 3 days. He was doing fine and eating but shy. I did a water change last night as my nitrates were about .40. Nitrates are down today. No ammonia. And I come home and he's upside down. Still breathing though. I grabbed a bucket and got water from my DT and put him in with a air hose. I don't know how to add a pic. But behind his gill looks discolored and maybe swollen?