Despite knowing almost nothing about Project Ukulele, I agree that the inclusion of an unnamed goldfish that taps the side of his bowl three times in succession would really tie together the game's entire experience.
Let's continue to fight the good fight for a goldfish that taps his bowl three times! If they don't do this, they don't care about the fans and probably wouldn't even care if we had terminal illnesses.
Speaking of terminal illnesses, I would even be OK if the hypothetical unnamed goldfish that taps on the side of his bowl three times has a terminal illness in the game. It seems something like that could, perhaps, continue the spiritual saga of fictional goldfish we might have known in the past.