All fish are currently in a QT tank. They’ve been through 30 days of Copper Power @ 2.25 followed by 2 doses of API GC. Everything had been going smoothly until today when I found one clown laying on its side, breathing heavy, and turned a very pale white. It does not appear to be covered in a white slime commonly associated with Brooklynella. I did notice this clown acting slightly odd the past couple days - hiding in a lower corner with its face pointed downwards, but it was still swimming freely and eating very good just 24 hours ago. The remaining fish - 1 more clown, Tomini tang, Midas blenny, coral beauty, and watchman goby all seem normal. Not sure if there’s anything I can do for it at this point, or if this is something that may spread to the other fish?