tried that, my girls got scared by it, cannot blame them, looks like an alien space ship.
so used a prescription bottle color collar as a floater. works much better, they actually jump through it to get the food. only thing is their eyes are not that great so they kept bumping into the rim of the collar, i hope it does not hurt too much. it does train them to follow the ring and eat nicely or not so nicely sometimes. but it traps the pellets so the amanos cannot get to it.
photo courtesy of Target: