Yellow Tang aggression towards reflection?

[Chameleon]

Hey yall,
Today after scraping my glass i noticed my tang freaking out over its reflection. attached is a video. is this aggression bad for its health? any tips for preventing it.
[video=youtube_share;stDFJwY6FeE]http://youtu.be/stDFJwY6FeE[/video]

 

[UCedumacasion]

Let your tank get covered in algae so he can't see it!

I had one do this but he eventually either got tired of it or figured out that it was a reflection and gave up. I wouldn't think it would be bad for its physical health unless he started hitting the glass, to me they have always seemed like a high anxiety fish, and there's nothing you can really do about that.

 

[Loki]

Ok. Here is my question. Can he see his reflection? I mean when we look through the glass and water into another pain of glass we see a mirror image. I have just assumed that is what the fish see. But I don't think this is true. If anything it would be like us seeing our face when we look into the tank right?

Maybe he is wondering where the algae went.

 

[UCedumacasion]

I don't know I mean I've experienced several wild caught fish having trouble understanding the limits of a tank. I swear its like object permanence for fish. It seems like they have to learn how to see beyond the mirror sometimes (I've noticed this more with tangs than anything else)

 

[Lynnmw1208]

My kole tang does this as well. he is worse than yours and tail slaps the glass. I got him when he was really little and didn't start doing this until he got to about 4". Nothing I do deters him from doing this. I was about to let coralline build up at the bottoms of my glass and I think I just might.