Betta Fish: Not enough oxygen?

Here is my little girl lightning mcqueen(ie). I got her on monday and she has been doing great in my 6 gal tank, but today I came back home at night and turned on the light to check on her and she was almost not moving close to the surface.

I tried feeding her but she barely ate so I started freaking out. She kept near the surface and gasping (I think) for air. I freaked out and turned her fitler on higher. I had it on a low setting because otherwise she just gets propelled agains the glass when she swims behind it (the current is turned towards the glass).

I did a nitrate and amonia test just to be sure and they were both fine (liqued test).

She seems to be okay now, moving around and looking at me and not constantly coming for air but if she goes behind the filter she does gets swooped away by.the current. Not very far but I am scared this will hurt her, but I am also scared if I turn it to a lower setting again there will not be enough oxygen again and that I won't be on time.

Anyone have simular problems witj their tanks? And how do I make sure the oxygen flow is better? I have got a pretty good amount of plants. Could it be the biofilm on the wood? Will she be okay with the higher current or will this also harm her?

https://www.reddit.com/gallery/1vu0p4e

Posted by solarlein