Skin changes during treatment against Costia/Ichthyobodo
My female Betta has had white blotches on her back for a couple of weeks. I found out they may be due to Costia, and have treated accordingly, but nothing has improved. Quite contrary, she now has a black spot on the back that looks as if she got burned.
that may indeed be a sign of healing: The skin is damaged by the parasite ifestation, and these spots look accordingly when the parasites have been removed - before that, it was simply covered by the parasites and the skin slime.
She does not show any other outer symptoms. She behaves entirely normal and eats well.
This is a good sign - just continue observing at the moment and ensure good water hygiene, that is sufficient. I am confident that the fish will get a little better every day!
Dr. Bodo Schnell