Yes, any fish smaller than it. Do not put it in a tank with tropical or Saltwater Fish because its not certain if it will attack, or even kill itself. Every betta fish is different, so I wouldn't take the chance. If you mix it with another male fish, they will attack each other to death. If you mix it with a female fish, they will mate.
yes betta fish have to live alone or one will kill the other.
Male Betta's are solitary. They cannot be placed with other fish. That's why they are known a Japanese fighting fish. They will kill other fish for territory.
a male Betta will usually like the company of other fish but will fight or kill others of their kind also they might fight guppies cause they look similar to a female Betta.
No, because they are fighting fish and one of them will kill the other.
Beta fish do NOT like other fish, they may try to kill the other fish or get seriously injured by the other fish.So probably not.
no because the male and femalebetas are the type of fish that live alone. therefor since their opposite sex then there is a chance of them being OK with each other, so if there is another fish with them then they will attack it and eventually killing each other.
No, probably not. The males would be more likely to kill the females.
The Betta fish want to kill eachother. That's what all Betta fish want to do, that's a natural thing.
it could be for territorial reasons.
No they would kill each other in less than a minute
No. Betta fish will attack each other no matter the sex.
Male Betta splendens fight with other male Betta splendens so the answer is most other fish will not fight with a Betta in the same tank. To try to list every species of fish here would be impossible.