Courting belly dance or submissive behavior?

[Claude-Michel Prevost]

https://www.youtube.com/watch?v=KqzTU2ocII4&feature=context&...

All 3 related clips are here:

https://www.youtube.com/user/oshogoun/videos

Back to:

https://www.youtube.com/watch?v=KqzTU2ocII4&feature=context&...

The male with the red spot on the nose is in the tube on the left. 

He's been chasing both females around for the last 2 days.

He's particularly stubborn with that one female - I assume it's a female, I did check for 2 spots on the lower belly, chasing her around, biting her belly and sides, but there is no blood and she doesn't run to the empty tube on the right.

Here she is, standing up while he watches. Then he will bug her again.

Courting belly dance? Submissiveness? 

There is no blood or overt violence.

And, he has not redone any nest since his transfer from the other aquarium, where he was really hot for another female - which I still have not been able to capture since she's so gifted at escaping my nest.

Questions for the group:

Seen that before?
It is safe?
Is it expected?
Should I replace him with another male?
Should I get him his favorite female?
Should I replace the present females?
Should I leave them together? 

Thanks in advance.

Cheers,
Claude-Michel

[Sheri Schmeckpeper]

Oh, my! Who would have guessed? Well, that's one small mystery solved!