Don't rush into treating with all sorts of different things. He looks healthy, and from the impression you're giving he is behaving and eating nomally. Sometimes healthy fish just do long white stringy poos. It can be part of a normal bowel habit. It's when it's all the time, or a majority of the time, that it probably indicates a problem.
As you have some of the Jungle parasite food, then why not give him some of that for a while, and then just monitor his poo, his eating and general health. I'll bet nothing else is needed.
