Is this HITH or not on my flowerhorn?

[Johnny1997]

So my flowerhorn have a hole in the back of the kok by the dorsal fin. These pictures show the hole are white color but it's actually red and I can see "red string like" so I don't know if this a damage or HITH. Thank you

So far I put salt and seachem prime.

 

[Johnny1997]

Here are some more pics, it's difficult to take a picture with him since he's always swimming and always active.

 

[kelman]

Could you take him out of the water? take a good picture and put him right back in.

 

[Johnny1997]

I checked last night while the fish was in sleep mode, I notice that the dorsal fin will close up the hole when my flowerhorn was not swimming nor active. I think it's not hith nor injury, it's just a dorsal fin that made the hole.