What is this on my anglefish

[q8cyu]

Hi, my flame angle recently developed a white scar on his top fin I’ve had the fish for 6 months and a few days or so he just got this
I have not added any new in the time this developed my best guess is an emerald crab attacked it in the night also the fish is still eating
The scar shows all the way to the fin bone and it turned transparent
Any idea what it might be and if I can let the fish heal on its own as I can only take it out if it is a must due to the rock work thanks in advance

 

[Sharkbait19]

Is the fish acting off at all?
I doubt a crab could do that - I’d be more inclined to believe it is either aggression or infection.

 

[q8cyu]

Is the fish acting off at all?
I doubt a crab could do that - I’d be more inclined to believe it is either aggression or infection.

I it’s acting normal I just found it’s fin like that a few days ago and no other fish have that it’s just the angle fish