Strange behaviour

[AVVITT]

Hi people. Just wanted to get some feedback regarding my Kole tang. A few days ago I noticed a lot of scratches/marks on one side of his body and both his scalpels sticking out.
I have a column at each end of my tank (for the inlet and outlet pipes) which is mirrored and he seems to be doing some sort of strange dance/ritual in front of the mirror then swimming up and dive bombing the sand and the side glass so hard at times you can hear the thud.
I cannot work out what's going on but he's doing it constantly now except when I drop food in and then he feeds perfectly normally until the food it gone then he goes back to being weird!

I've attached a couple of videos

 

[CoralB]

Might have something to do with the mirror

 

[i cant think]

Hi people. Just wanted to get some feedback regarding my Kole tang. A few days ago I noticed a lot of scratches/marks on one side of his body and both his scalpels sticking out.
I have a column at each end of my tank (for the inlet and outlet pipes) which is mirrored and he seems to be doing some sort of strange dance/ritual in front of the mirror then swimming up and dive bombing the sand and the side glass so hard at times you can hear the thud.
I cannot work out what's going on but he's doing it constantly now except when I drop food in and then he feeds perfectly normally until the food it gone then he goes back to being weird!

I've attached a couple of videos

That is aggression, the mirrors will reflect the fish and they will get all aggressive as the tang is trying to establish dominance.
Here’s my tang going all out with his own reflection in the mirror. If possible, remove both mirrors as this will stress the tang out too much if he does it constantly every day.

 

[AVVITT]

The weird thing is, he's been in the tank for about 6 months so why now?
Also, the mirrored finish is part on that section of the glass so there's no way I can get rid of it

 

[i cant think]

The weird thing is, he's been in the tank for about 6 months so why now?
Also, the mirrored finish is part on that section of the glass so there's no way I can get rid of it

He may now be maturing, very little is actually known on tangs and harems do it is possibly they form harems as juveniles and then pair off as adults.