Bangaii Cardinals

[halwake]

Had a male and female Bangaii. Male died after holding. Looking for new male. Purchased a slightly smaller than the original female Bangaii and she chases it to the other side of the tank. It has onlt been 1-2 days. I suspect I have a second female. Should I give it more time or keep looking for a male? I know they are difficult to sex especially when Juvies, but usually by behavior you should be able to tell especially when you are certain of the sex of one of them you have. I tried to do the venting method on the new one but still could not tell.