Help: My bichir has contracted a rare disease.

My Lapradei bichir recently developed a condition that’s causing its scales to peel off. At first, I thought they might have been fighting, but then I noticed it was more widespread (as shown in the photo). I’ve tried asking other bichir keepers, but it seems no one has encountered this disease before. Could anyone help identify if it’s a fungal infection or a parasite, and suggest treatments? It seems to be spreading to other bichirs in the tank.

Currently, I’ve separated them into a different tank and am using Polygard and StressCoat, but there’s been no improvement. Thank you, everyone.

Excess mucous on a wound.
Add salt for a few days and if no improvement use a broad spectrum medication that treats fungus and bacteria.

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Before you treat the fish do the following.

Test the water for ammonia, nitrite, nitrate and pH.

Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate. The water change and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.