Originally Posted by clm
melafix can coat the gills making it difficult for fish to breathe. I never use the stuff and never will.
I agree. I've used it before and had nothing but problems. I follow the dosing instructions and still had it kill off biological bacteria (which it claims not to do - I think it may have suffocated them), and kill a couple of fish by causing respiratory issues. After adding it to a tank I noticed every single fish was breathing heavily and I ended up having to do a massive water change to get the stuff out of the tank. I have a whole gallon bottle that has only been used twice because I refuse to ever use it again.