What fish can go with a beta fish?

If you can, use a divider to introduce new fish. Or watch them for over an hour. Bettas usually check out new fish, but then get bored after an hour with flaring up and chasing. Generally, if he doesn't calm down after the first day, they aren't compatible. If it nips at all, I wouldn't risk keeping the other fish there. Mine never nipped new fish. :)

But I have female Bettas together with one male Betta, I have a few female and 1 male with my plecos (Minimum 40+ gallons for that setup though), and I have one male Betta with my minnows. He doesn't bother them at all, in fact it's quite entertaining to watch.

My male Betta will watch the minnows, who like to race across the tank. After several minutes, my Betta will try to imitate them for a second and then come back to the top of his cave, as if to tell me the minnows are idiots and he can't understand why they race all day long. lol

My plecos have never injured a Betta. My Bettas have never injured another Betta.

Well, one time I had a problem with one of the females. Poor thing got harrassed by the other females, not the male though. I watched for ten minutes, before taking her back out and putting a divider in. I kept the divider for a few days and then tried reintroducing her. No problems. Sometimes, that happens. Just use a divider for a little bit longer and try reintroducing them.

Always watch them when bringing home a friend. :)

Wow, I'm long-winded. lol Sorry. But hopefully, I convinced you to have hope of finding a compatible mate for a Betta. :) Some males are too aggressive for even females, though. (I have one) He's the one with the minnows and he's fine with them. I think he hates picking on smaller fish. lol Because all my Bettas are bigger than him and he attacked them.

I have 6 zebra danios with my crowntail betta in a 30 gallon. In a big enough tank you can add neon tetras, danios (not giant) and tetras. As long as its a big enough school it shouldnt be a problem. It does become a problem if u only have one or two schooling fish since they do become fin nippers. And colorful fish the betta might mistake it for another betta and attack it.

I've even seen people with two male bettas in the tank living peacefully but it has to be a giant tank with lots of plants to hide in

I currently have Corydoras, Otocinclus and Khuli Loaches in with my Betta and he leaves them alone. Anything around the Bettas size, or a tad larger that is fast and has no exciting colors should be fine. Some Bettas are picky about tank mates though so it is really up to your Betta, not you.

Preferably none, because Betta's can be really picky...right now I only have a couple snails with my betta...Don't want to take any chances..I have tried Neon Tetras, Guppies, and a few others and it didn't end well..