Friend bought this purple tang proper way to treat

[Clutch]

My friend bought this tang he says there’s no white spots but I noticed the huge black spot on the side. I’m not sure what it is and how to treat it.
I know if you treat certain diseases with copper it can stress the fish out even more and kill it
Any advice or parasite diagnosis is appreciated

 

[Hemmdog]

My friend bought this tang he says there’s no white spots but I noticed the huge black spot on the side. I’m not sure what it is and how to treat it.
I know if you treat certain diseases with copper it can stress the fish out even more and kill it
Any advice or parasite diagnosis is appreciated

Just sleeping

 

[User]

Just sleeping

Agree

My PT goes grey and white with the same black patch when it’s asleep, or super ticked off like during today’s 100% water change. He didn’t like being in a partitioned 10 g at all

 

[James M]

Almost all fish will often change color when sleeping or as a stress response

 

[ckalupa]

Agree - talk about a fish that changes from deep awesome colors to pale and faded! Purple tangs certainly are up there. Gem tangs get all “blotchy and patchy” (Are those real words?) making you think you need to do a FW dip and treat something immediately.

 

[miyags]

Check for ammonia,looks stressed to me.Looks like it's in a brand new setup.Was the tank he's in cycled?

 

[4FordFamily]

That’s his sleep or stress coloration. I’d advise copper power, Hanna checker to measure, ammonia alert badge, and BioSpira for biofilter to keep ammonia at bay 14 days if transferred to new sterile QT day 14, or 30 days in one QT

 

[4FordFamily]

Edit:

I read white spots on the original post, you said NO white spots.

No need to treat without other symptoms, my mistake!