I have a pretty feisty CT, but he's calm enough not to attack/eat my ghosties. They'll be practically climbing on his face when he waits for food, and he'll just sit there and let them. I've seen him chase them a few times, but never for more than a few seconds.
My plakats are BY FAR the most active. They buzz around the tank almost constantly, but I suppose its easier for them with the smaller finnage. (for proof, here: http://www.youtube.com/watch?v=tgvd14Qxodk
- He does this all day long, and so does my new DSHMPK)
I have a PK king who is laid back. He's aggressive enough to flare and nip at my finger if taunted, but that's about it. Just kind'a cruises around his tank pretty slowly.