I have a yellow lab that appears to have white stringy feces (mucus). A couple of them are skinnier than the other labs; but I think they may be females because I saw at least one of them holding. Anyway, they are very good eaters, are excited to eat, and are pretty active in the tank. They do not hide for the most part. One does take a break from the action in the tank at times. There are no sunken or bloated bellies that I can tell anyway. Just in case, I started to treat with general cure first and the second dose with seachem metro. I added epsom salt (2T. per 10 gallons) and fed lightly with green peas. They seem even more active after the treatment of epsom salt. I am doing another water change tomorrow (48hrs.). I don't want to misdiagnose and stress the fish with unnecessary interventions. My question is, could this be something else other than parasites?