Bubbles On Surface Of Tank!

[nataku]

Hi, i had my tank for 3 weeks already.
I settled my plants in and have 3 algae eaters and 6 shrimps, the tank was doing well until I noticed a few days ago that bubbles started appearing at the surface of my tank and they are all at the side near where my filter is.

Are the bubbles harmful? And what is causing them?

 

[philfista]

I had the same thing but they are gone now. Dont know what they are.