Fish Behavior?

[FishPharm]

There are times where my Copperband butterfly spends a large portion of his time swimming up and down with his nose against the glass on the left side of my aquarium, mostly after the halides go off and the actinics come on. Now my newly acquired Bellus angelfish who spent a good week acclimating to the lights by hiding in the rockwork has taken to this same behavior. However, the Bellus will do this all day long, taking a breather here and there. They both eat well. There are 10 other peaceful tankmates in my 180. Neither are threatened or harassed.

Is this something to be concerned about? Or is this something fish do and grow out of?

Thanks.

[FishPharm]

Anyone?