Why Is My Blue Dwarf Gourami Swimming Against The Glass?

[Synaesthesia]

Hello,

My blue dwarf gourami was introduced to my tank yesterday and was fine until a few minutes ago. I got home from work and the moment he saw me he started swimming frantically against the glass and has been doing that for almost 10 minutes now. He just goes up and down. He's not smashing into the glass or anything like that, just kind of pressing his face against it and going up and down, sometimes side to side.

Is he sick? Looking at his own reflection? Just being a dork? Is he trying to get air? Does he need an air pump?

Please help

P.S. tank is fully cycled, water tested and everything is fine. no white or black splotches on his body.

 

[Synaesthesia]

He stopped swimming against the glass, but just now he violently attacked a plant. It wasn't moving or anything, he just attacked it. O_O

Is this normal?

 

[Mr Bliss]

Gouramis like vegetables. They'll nibble at algae and occasionally tear at soft plant leaves (well at least blue gourami does that).

Do you have a lot of water current in the tank? That could be a cause for the swimming against glass behavior, as they prefer relatively calm water.