White patch on girl pink salmon betta's head

[Vivo]

I put my betta in a community tank 3 days ago.  I noticed a distinct white circle on top of her head yesterday.  Hoping I just didn't notice before (I've had her for 3 weeks), I can't stop noticing it now.  I put her in quarantine again and am trying to figure out what to do.  Water parameters are:  pH 6.3, Ammonia 0-5 ppm, Nitrite 0 ppm, Nitrate 10-2- ppm.  I do 10% water changes weekly with Seachem Prime.  I did one yesterday.  She is acting and eating normally.  Help?

[Lucyn]

The first thing I think of when you describe a white patch on the head is the disease "hole in the head". It usually occurs because of parameter problem in the aquarium and some fish are more sensitive to those toxic parameters, even if other fish show no signs of discomfort. It could be a nip from a fish, sometimes fish bruising can turn white. Keep that water very clean, the more water changes the better. I'd increase either your volume or frequency of water changes temporarily, if it doesn't get better within a few days I'd start treatment with your go to bacterial disease treatment or  light amounts of salt. 

Edited August 19, 2020 by Lucyn