Just got home, asfur is dead.Copper safe is fine. As jay was mentioning the suspected flukes may not be seen and the dip can unnecessarily stress them. Will let @Jay Hemdal comment on that. As I’m not in a place I can leave a long answer. Can you remind why you think the other fish had flukes. Maybe I. Misremembering from the other thread but antibiotics were recommended for fin rot. Note I’m not saying the fish does not have flukes just your impression. Can you also do more pictures and an updated description of his things are since this am? Thanks!!