air stones are perfectly fine to put in tanks with bettas, just make sure it has an adjustable valve so you can put it on a low setting and it won't make a stressfully strong current.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger-all down here on Earth.
Loki/Grendel/Gail/Beowulf/Camilla/River/Bathory/Arwen/Lafayette/Deb/Jack Skellington (soon)