PlanetCatfish.com

The danger of including wc fish in our collections is that we risk importing unwanted creatures. One of my Orinocodorus eigenmani presented me with just such an event. I redid the 120g (480l) tank that houses my large doradids and in removing the inhabitants. I noticed the bubble on the side of one of them. I thought it had an injury from trying to share a hide with one of the other cats and I was really worried that what I was seeing was intestines.
I was encouraged by another hobbyist to perform surgery and so I obtained some clove oil and took the plunge. Any parasitic worm not in the intestines can only be treated by surgery, unfortunately. I will be needing to monitor my cats for more worm bubbles.

Found the following while trying to learn more: https://edis.ifas.ufl.edu/publication/FA091

It looks a bit like dermocystidium and that's a fungal problem.

kruseman wrote: ↑16 Feb 2022, 20:05 It looks a bit like dermocystidium and that's a fungal problem.

Can't say I like your diagnosis but after doing some googling I think you are correct. I'm even less happy about there not being a treatment.

Great article you linked. Thank you.

IDK about what your fish had. Not enough experience.

I had one run in with nematodes but those were macro worms, many of them, embedded deep inside the muscle tissue of a rescue 1.5ft peacock bass.

Viktor Jarikov wrote: ↑16 Feb 2022, 21:58 Great article you linked. Thank you.

IDK about what your fish had. Not enough experience.

I had one run in with nematodes but those were macro worms, many of them, embedded deep inside the muscle tissue of a rescue 1.5ft peacock bass.

Wow, how did you remove that?

The following is from a research paper about juvenile catfish in China infected with dermocystidium:
Infected juvenile southern catfish were emaciated, and swam sluggishly on the water’s surface of net cages in the river. The infected catfish were covered with structures looking at first sight like white worms or winding white threads, which were subcutaneous (Figs. 1 to 3). Closer examination showed these structures to be cysts of the Dermocystidium sp., which were only observed in skin and fins of the catfish, and were not found in other organs. Cysts of different sizes (3 to 20 mm in length and 0.15 to 0.35 mm in width) were located in the dermis in an irregular way (Figs. 1 to 3). The anal fin was often found to bear cysts (Fig. 3). The infected sites of the fish skin displayed hyperaemia and oedema (Figs. 1 to 3). The epidermis at some parasitized locations was ruptured and had been shed (Fig. 2).

https://www.int-res.com/articles/dao200 ... 65p245.pdf

The peacock died, I cut it open. Found easily half a dozen of the nematodes. But it sounds like your problem is not worms, despite the white worm-like or thread-like appearance. I am glad to learn along. Never heard of the dermocystidium.