Compatible fish for bettas

Question
I was wondering if there are fish that don't require a filtered tank and are compatible with a female betta?

Answer
Hello Christine-

You can put other female bettas in with yours, if they are about the same size and don't start fighting when you introduce them.

Other fish are catfish, like Raphael catfish and bumblebee catfish. They are pretty hardy and could probably do fine without a filter. Most other free swimming fish need at least an airstone to do well - I would avoid bichirs and eels, because they might eat your girl!

-Amber Worman