My juliI corydora has a white puff ball like fungus on one fin. Was small at first but seems to have gotten bigger almost covering the whole fin. He seems to be his happy hyper normal self, no signs of distress and his tank mates haven't showed any of the same symptoms. ( 1 julI cory, 4 adf's, betta & pleco) I barely spotted the same fungus on the lid of the tank while doing a recent water change and scrubbed it off. I have done a lot of research but can't seem to find the exact name of this fungus and what medication would be best for a cory?? I attached pics its on his right fin. Any advise would be grately appreciated!