i have a male guppy that I have had sense I started my aquarium which was 4 or 5 months ago. Well woke up today and his tail looks like something clawed it. Don't own any cats and while I have fish that might nip fins I haven't seen any doing so to others. What could have happened? Changed the water a few days ago and I don't have any new plants. Could it be old age? Is my best buddy getting fragile? I have him in a seperator with some female so he doesnt freak out.