Yellow tang aggression... toward his own reflection

[Brett S]

I cleaned my glass today and my yellow tang, who has been in the tank for years and through countless glass cleanings, has suddenly discovered that he can see his own reflection in the glass. And he really really does not like that other yellow tang. This tang has never really shown any aggression toward anyone else in the tank and I’ve never seen him attacking his own reflection like this, but he goes all out swimming up and down trying to swipe his tail against the glass. I’m a bit concerned that all this aggression is stressing him out and I’d like to get him to stop.

Even though I cleaned all of the glass it‘s just one corner that he seems to upset with. He keeps coming back to that corner and posturing against his reflection and attacking it, then swimming away only to return a few minutes later.

I just tried to tape some white paper to the tank where he’s seeing his reflection hoping that the white background will make it less obvious. Any other thoughts about trying to stop this behavior? Like I said, I imagine this has gotta be stressing him out a lot.

 

[Rp8]

A video would be cool to see, just for entertainment purposes.

if he has claimed that spot as his, you could try rearranging your tank, forcing him to pick a new spot. I do this with mine if I'm adding fish, or periodically, bc if I was stuck in the same place forever I might go a little crazy too.

 

[Rp8]

and the paper was a good idea, by the way