Okay just bought him, and after looking I realized he had the white bumps on his right pectoral fin.. 
I treated ich on my other fish recently with the salt method, are knife fish sensitive to salt? for my 55gal I used a salt ratio of 0.02% and it cured up fine, would this work for the knife? or would it kill the knife?
This is my first one and I dont want him to get sick, the ich seems to not be bothering him and only on the one fin..

I treated ich on my other fish recently with the salt method, are knife fish sensitive to salt? for my 55gal I used a salt ratio of 0.02% and it cured up fine, would this work for the knife? or would it kill the knife?
This is my first one and I dont want him to get sick, the ich seems to not be bothering him and only on the one fin..