The only way to be sure what it is, is to get a swab of the area, and take he sample swab to a lab, (or university) that could analyze the problem.
Many fish maladies (viral, fungal, bacterial) look very similar until examined under a microscope. There may be a veterinary lab near you to try. $$$
If it is lymph, that is viral and the only thing to do is let the immune system take care of it, there are really no treatments for that virus.
If bacterial, you will need to know if its gram +, or gram -. Some antibiotics are only effective for one or the other. Bacteria sometimes get more virulent in higher temps.
It does not look fungal to me, those infection are usually much more tuft like.
And doesn't look like ick.
Below is a bad case of ick.
It was cured soon after using only water softer or rock salt, at
Many fish maladies (viral, fungal, bacterial) look very similar until examined under a microscope. There may be a veterinary lab near you to try. $$$
If it is lymph, that is viral and the only thing to do is let the immune system take care of it, there are really no treatments for that virus.
If bacterial, you will need to know if its gram +, or gram -. Some antibiotics are only effective for one or the other. Bacteria sometimes get more virulent in higher temps.
It does not look fungal to me, those infection are usually much more tuft like.
And doesn't look like ick.
Below is a bad case of ick.
It was cured soon after using only water softer or rock salt, at
