Pic of my mandarin *sigh*

[Stretch]

If food supply isn't an issue you can, You can keep male and females together. They should become a mated pair

I don't know about female and female, I don't think it would a problem

Male and male will probably fight to deah.

[Aquattro]

Since they're easy to tell sexes, creating a pair is fairly simple. Of course you'll need to have twice the food for 2, which could be tough.