Trying to identify what appears to be consuming my Betta's dorsal fin.The fin looks like it is swelling or rolling back on itself.The area where it is occuring have a bronzish gold color compared to his normal deep blue.No other parts of his body or other fins seem to be affected,and doesn't seem to affect his normal behavior.He is feeding,flaring,building bubble nests as usual.He is the only fish in a Marineland 6 with the same plants and chunk of Mopani wood that was setup over a year ago.No additions to tank or changes in diet(Hikari pellets,no fresh or frozen foods that might have introduced parasites or bacteria).Weekly pwc's of dechlorinated water since setup.Sorry no pictures,don't have a digital camera.No inflammation or ragged edges or wooly spots.