Fish tail fin split, is there cure?

[SethKim]

My Hippo got this long time ago, 3~4 yrs ago...never healed so I'm wondering if some other hobbyist had similar experience and if they know the cause and cure.
I've been soaking selcon, which helped with scars and lateral line diseases.
All my fish including this one went through cocktail antibiotics. But I don't see any improvement.

 

[Deanos]

My hippo tang's tail was split for several years as well. It actually grew as it did. Here's a few shots before I gave it away last year.

 

[Deanos]

Here's a few shots I found when the tang was even younger