The tail fin has these 'extensions', for lack of a better word. Not at the top and bottom, but at irregular intervals down the fin. The con has shown above average growth; he outgrew his siblings and had the noticeable beginnings to a nuchal hump around 5 months old. It could be a fairly common thing that I haven't witnessed before. Any thoughts? (Apologies for the blurry pics. Click on them for a bigger image).