One of my female juvenile guppies has a stringy, white poop hanging off of her. I know that this is a likely indicator of parasites but was wondering whether anyone else had any other experience with them apart from parasites? My tank has been established for about 6 months now and none of my other guppies have shown any signs of parasites. Should I just treat the whole tank and hope for the best? Also some of my other guppies have been doing really tiny black poops – is this normal?