Thank you TwoTankAmin for your help with this. I also found that 95% of information in articles about columnaris dealt with commercial fish. I have, since this initial inquiry, been using methylene blue+salt baths with modest success. The lesions remained. Yesterday I was able to acquire some Merbro...

I have a Corydoras sterbai with a lingering slow growing columnaris. My question is: How much salt can a C. sterbai tolerate? I did a course of 13 days with Furan-2 and Kanaplex. Lesions faded but remain. I am treating her with methylene blue + salt baths twice daily now. After 5 days of baths the l...