Angel Trailing White Thing

[cambojnr]

So my angel is trailing something from where i think its fin is healing from a bit of a tear, is it just excess slime, our something more sinister as I am useless at diagnosing and never find anything similar when I search for it?

 

[WILDER]

Does it look like a strand of cotton as it hard to tell in the pics?
Does it wriggle or move?
Does it have a Y shape tail on the end?