Can a damaged dorsal fin recover?

[ScubaSteve]

So for the past year I've been fish sitting a friend's Goldstripe Maroon Clownfish. To put it nicely this fish is a $%^&ing !@#%$##.

Well, today ^%#er finally crossed the line and attacked my beautiful randall's goby who is by far my favourite fish in the tank. The clown did a pretty good number on my goby's nice big dorsal fin.

What I would like to know is, can a dorsal fin recover and regrow to an extent or do I now have a permanently mangled goby?