I have a red tail shark and it has been itching on the substrate. It's weird because I only see him itching on the substrate. I thought it was flukes so I dosed with prazi-pro and it seemed to go away and then like 1-2 weeks later It came back and I dosed again and the same thing happened. So idk the problem. I heard that the flukes will lay like eggs that can stay for 20 days. Could it be that? Also it looks like on the back of his fin that is red it looks like fin rot may be starting. I tried aquarium salt and it seemed to go away but then. It came back like 3 weeks later I think. I am not sure if it even went away I just think it did. But if I treat that I don't want to use salt because I heard aquarium plants are sensitive to it. What do you think it is and how should I treat it? Thanks!