if you've seen his tank there isn't anything to scrape against, that rules that out. i can't really tell what it is, but deffinately add salt to the water, that should help.
if you don't have a QT tank, you should get one.....but you could just use a large tupperware box or something of the sort with a heater in it and a seeded filter from your main tank. you should still treat your main tank with salt or primafix as a preventative.
