My poor Cory is in a bad way, can anyone suggest a course of action? This started yesterday and seems to be spreading rapidly, water tests fine. I had the same thing happen to another Cory a few weeks back and it died, I can’t put it in quarantine tank as have molly fry in there at the moment. Can I add some aquarium salt maybe? It’s a 125 litre tank and have had the Corys for a couple of years.