There has been white around the mouth area of celebes rainbow. It has red around peripheral area. Also seemed to be white just inside threadfin rainbow mouths. Have them quarantined but am treating main tank as I see some small signs in most others too.
Have been figuring it for mouth fungus, cotton mouth, cotton wool etc. In other word I've been treating for columnaris. I had this once before but is was on body not mouth area and fish didn't do well.
Have been treating with first erythromycin, since I had some already, even though this is gram positive. Purchased some furan two, and maricyn two and have been treating a total of four days. I haven't seen improvement. Ordered some kanamycin but won't be here for a few days. I am checking levels and dealing with some ammonia as I've had the carbon out for treatment. Doing daily water change and using prime to combat.
These are lousy pics but here. I'm not sure it is columnaris, but could be since it takes so long to treat and is difficult to kill. It doesn't really have a cotton fuzzy look to it though.