Is my clownfish acting weird?

[PegasisR]

So recently i noticed my clownfish swimming in place and in addition doing a jerking motion, like its twitching or something... could there be an underlying issue? Other than that they eat and swim around normally

 

[James M]

Is there another clown in the tank ?

 

[PegasisR]

Is there another clown in the tank ?

Yes

 

[Phil D.]

That clown is submitting to the other one as the dominant.

 

[James M]

What he said^^