Not sure what these white patches are. Need some help .
 

So I had my bristletooth tang for almost a month and a half now and he's developed a few white patches on his body. He is in my main tank and I haven't been able to quarantine him yet . I was wondering if someone could please tell me what my fish is sick with and what treatments should I do to cure it. Thank you .

Pictures please

How long have you seen this? He is eating? Your tank has corals?