Bettas rarely ever have problems with the smaller bottom feeders (ottos, small corycats) and small peaceful community fish.
The problems with bettas stem from fish that looks like the betta, or occupy the same territory (the betta will attack anything that looks like it, and will fight for territory) So you don't want to put it in with other semi-aggressive medium/top dwellers, or things like fancy guppies generally.
Small nippy fish that are much faster than the betta are more problems TO the betta than FROM the betta. That's why I suggest you stay away from neons, but can recommend from experience other tetra families.
I have only ever had 1 betta actively chase ottos, and that was only when he could find them, and he was never able to actually harm them in any way I could see. And he was so aggressive he'd flare at the hint of a reflection he'd get from the glass *in his own aquarium* almost non-stop if the light was on.
Cories are a bit more iffy, because they're generally bigger and easier to see, but I've never had any significant problems with them.
The problems with bettas stem from fish that looks like the betta, or occupy the same territory (the betta will attack anything that looks like it, and will fight for territory) So you don't want to put it in with other semi-aggressive medium/top dwellers, or things like fancy guppies generally.
Small nippy fish that are much faster than the betta are more problems TO the betta than FROM the betta. That's why I suggest you stay away from neons, but can recommend from experience other tetra families.
I have only ever had 1 betta actively chase ottos, and that was only when he could find them, and he was never able to actually harm them in any way I could see. And he was so aggressive he'd flare at the hint of a reflection he'd get from the glass *in his own aquarium* almost non-stop if the light was on.
Cories are a bit more iffy, because they're generally bigger and easier to see, but I've never had any significant problems with them.