Do Rummynose Tetras Naturally Open And Close Their Mouths Rapidly?

[SamLovesCorys]

I have tested my water with a reliable liquid kit, and added my air pump again, but the Rummynoses are still moving their mouths rapidly. Is this just natural behaviour? My Black Neons are doing it a little as well.

Thanks, Sam

 

[onebto]

The main way of getting oxygen into your tanks water is from surface disturbance from your filters water output try adjusting it so it ruffles the water up a bit more.

Regards onebto.