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?