the medicine that you have to use for drospy will mess up your cycle if you have another tank to put the guppy in I would advise you to do so dropsy doesnt spread but I wouldnt take any chances on messing up my cycle with the med. I wish you luck in treating your guppy but I hate to break this to you I havent seen a fish pull thre with it yet. But good luck anyway and I hope this treatment works for you.
If this acually works, its going to be like bringing a fish back from the dead. My dad saved my goldfish a couple years ago by giving it cpr, i dont know how that worked, but it did