One of my blue dwarf gourami's is the ruler of aqualand. He decides where he's gonna be in the tank, and then runs all the other fish outta his space. If he changes his space, everyone else is expected to not be there. He'll do other things like come up & nip me in the finger when I'm doing water tests. He even took a shot at the siphon hose today. The kids think he's great fun
What I think is great fun is this one little female barb I have. She's less than an inch long, but she'll come up every once in a while & nip him hard enough on the tail it sends him zooming around the tank for a couple of laps.