I'm sitting on the couch next to my Sushi's tank and running my finger along the side of the tank and he's following and flaring. I then took a pellet and pressed it against the glass and my finger and watched him try to eat it.
I have never seen him jump, so I decided to take the pellet that was "stuck" to my finger and hovered it over the water. Sure enough, he jumped out and ate it off my finger! It startled me at first, but I think I may have fun with this at feeding time.