[Torontotraders]

I suppose I should have asked this important queston...Is it a new fish in QT, or was in from your tank with good water quality?

If it's a new fish - Do a complete water change. Match your salinity, get the temp close to matching, and premix your copper treatment to match what's in there now...That is if you're using copper or maybe you're just doing observational qt, which means you likely shouldn't have a reason for bad water
unless you didn't get your filtration up and running prior???

I'll send you a pm, if you truly need Kanoplex, but that will only be a temporary solution...Your ammonia is likely off the charts, which means you should get some prime in the water until you change out your water (like asap).

To sum in up, your water quality is likely bad, that's why it's getting red spots/blotches...Again, if your water is off...Let me know.