Is this fin decay?!?!?!?
My fish has a thin black line on the very bottom of its fin
Here is a picture of him that i have edited on paint to show you.
I won him from a fun fair and it wasn’t there before?!?!?!
http://www.FinDecay.piczo.com
The black line on the picture is the blackness that has developed on his tail
Here is an answer from a goldfish web site http://www.petgoldfish.net/site/from-white-to-black-t56.0.html;msg161;topicseen#new
You have a common goldfish, have a look at the home page in the top left hand corner for more help 
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