Not sure if my fish has something wrong or not!!!

Dooz_nutz Member Posts: 34
edited February 2014 in Emergency Room
Also wanted to see if any1 can help in my tropical tank I have a red tail shark that just before his fin at the end has a green spot on both sides looks kinda shiny not sure if it's natural or not?
It's been there for over a month the fish seems fine dosnt bother him at all still feeds and does everything the same just not sure if it's some type of disease or what??????
I will post a picture soon as I can figure out how to on this cheers