A good filter for bettas?

[bettabax]

So when I got my lovely betta Dedalus, my roommate also got a betta but a different tank than me and she's having issues with her filter.

She has the hexagon tank from PetCo and the filter is:
a.) Definitely too strong. Her betta was super tired from fighting the current so she unplugged it and is looking for a new one
b.) it is supposed suction cup on the sides and it actually fell off of the wall and almost trapped her betta. Luckily he did not get caught but he was visibly stressed when the discovery was made.

What would you suggest for her as a good filter for a betta? I know you can baffle the filters to make the current less strong but the falling off the wall thing is also concerning. The tank is 2 gallons. Any help you can give her would be greatly appreciated!

[Pitluvs]

I have these in my 1.5g, its rated up to 3g. My bettas have no issue with the soft current and they suction really well. I have 4, no issues.

Tetra Whisper 3i