I agree with Lynda, my black one is a bit bolder than my striped kuhlis. I don't necessarily think it is more active, it just does more during the daylight hours than most of the striped ones. I will say that my striped kuhlis do that "dance" too. So cute.
I agree about being cautious of tank mates. You also don't want to put them in with anything that will see them as a worm and eat them. Mine are with angels, corys, pitbull plecos, rummies and platys. I have never had an issue with this set-up.
Oh, I also totally agree about feeding the sinking pellets at night and about having proper hiding spots for them so they feel comfortable enough to come out during the day. Mine like to play in my Amazon swords as well.
Mine is a busy-body, so here is the best shot of him that I have.