regal tail fin

[rocride]

Hi,

I have two large regal tangs and recently I notice that they have two different tail fins.One of them has a tail that it squared off at the very end and the other has what I will describe as two little trailing fins at the top and bottom of the tail fin.Make sense?

One tail fin looks like this | at the end and the other looks like this [

This kinda popped up on me and to be honest I don't think it's always been like this and if it was it definately wasn't as pronounced as it is now.I tried to get a picture but he's way too hyper.

Does this mean anything as far as gender goes or is it just how his fin is?
Is he a she??

Thanks!