Another newbie question..

[Jenn_737700]

So I have this pair of f.p clowns, that I just got about 3 weeks ago. They're doing well, getting along, eating good, no complaints there. The only thing im wondering about is that the smaller clown ( the male ) is getting somewhat darker and making these weird shaking motions around the female. Sort of like a mini-seizure. I feel kind of dumb asking, but id like to know why he's doing it?...

Thanks