Buddies for a Betta

Hi all,

I have a planted 6g tank with a betta in it. If algae ever starts
growing in this tank, I'm thinking I'll want something to eat the
algae, and I'm wondering what would work well with the betta - I don't
really like snails, so I'm thinking maybe shrimp or something like an
oto (but I suspect the tank is to small to keep an actual oto happy, so
I'm wondering if there's a similar fish).

Any suggestions appreciated.

Thanks,

Liz