I assume you have at least an 8 foot by 2 foot by 2 foot tank if you are considering keeping something with Oscars. Other very large fish like Pacu, large Plecostomus, Jack Dempsey etc can be mixed...
If your getting a female Betta... You should buy fish that are not it's size but also not to small. A good thing to do is to use my method of introduction. Take the fish to the tank with the fish you...
That is a yes and no Q. because yes some betta fish like other fish but some dont....that would lead you to one sad moment....(you know what i mean) By:Expert Serena