nothing as yet,i was going to try it if my fish got fungus,or body slime as it says on the bottle,also it says you can use it when adding new fish,i bought it because its a natural med and wanderd if it would be better?
to be honest i got it because my mollie looked like she had a small amount of fungus, but today she gave birth to many kids now she looks ok.so now im keeping it just incase ,thats why i was wandering about the loach.
as melafix is a natural product it is fine to use with any fish.
I would use melafix first for fungus over any other fungal medication as they are chemicals and not natural
IMHO, always go natural first and chemicasl as last resort.