Here are two diseases to look into, taken from Lupin's sticky on freshwater disease. I have no personal eperience with either disease. For treatment, I would do a large 50% water change and treat with Maracyn & Maracyn-Two. Great meds, when used together they can cure a number of different fish diseases. Keeping the ammonia and nitrites at zero is very important in the healing process, daily water changes if needed to keep both at zero. Avoid any ammonia removing product, water changes are the best and safest way to remove ammonia. Good luck!! Hope your fish get well. Patchy Disease
Symptoms:
As this seems to affect hillstream loaches more than any other fish species, it must be noted that the affected hillstream loaches usually have abnormally pale patches around their body. They may lose appetite as the disease progresses. Rapid breathing is also noticeable.
Causes:
Introduction via unquarantined fish.
Treatment:
Maracyn I and Maracyn II-Follow dosage as instructed.
Columnaris (Flexibacter columnaris)
Synonyms:
Cotton-wool, Mouth Fungus, Flexibacter
Symptoms:
White mouth with tiny filaments, white areas near edge of scales, clamped fins, fins start to rot in the later stage, fish struggles and sways near the surface
Causes:
This is bacterial infection which is very common in the aquaria and is very contagious. Immediate action is needed to contain it before it spreads to other fish.
Treatment:
Broad spectrum antibiotics, Sera Baktopur, Binox, Maracyn I & II, Kanacyn, Terramycin, Acriflavine, Furan, Copper Sulfate
Flexibacter columnaris thrives very well in warm waters therefore it is necessary to gradually lower the temperature to prevent it from progressing.