you could do female of either in that tank, maybe a male blue but yeah def not a male regular (at least not for life) blues tend to be much harder to care for though and tend to have sudden die offs if you dont get one with strong genes and tend to have deformities such as a beak face and things like that, but if you can find a good healthy looking blue thats already got some size on it then that would be good choice and you could put some tetras or something in with it