Starfy hails from a Gameboy advance series from Japan and a more recent title "The Legendary Starfy". Not only does he have a base in Japan and a new game available everywhere that did well, he was an assist trophy in brawl, so making him into a fighter may not be a stretch. In this game, he is the same size as Kirby in order to keep the fighters to scale.
B. Whirlpool: Starfy rotates to create a whirlpool similar to Meta Knights B standard.
<-B-> Starfy Spin: Basically what he did in brawl.
B^ Starly Boost: Starly appears beneath Starfy and boosts him upward.
B V Stafy Wheel: Starfy spins in place creating a damaging ring of water.
Final Smash: Omega Whirlpool
This is a triple sized, vaccum force, seroiusly damaging whirlpool that appears as Starfy jumps to the center of the stage and spins extremely fast.