Well, Orange Fish isn't in Smash Bros. He never got his drink either, and so I think its only fair that he gets paid back by getting put in Smash Bros. I mean, Spongebob gave him his pizza without his drink. How's he supposed to eat his pizza without his drink? Spongebob and Squidward were playing "games" with him, so in a way he is a character from a game, and for his moveset he could throw his pizza at the other characters, and his final smash can be him finally getting his drink.