I meant that link probably wouldn't have known that ruto was inside Jabu-Jabu, because it would be stupid if link purposely tried to get eaten without a reason. Sorry I may have worded some of my last post badly. Anyways it still doesn't make sense to me ruto was carrying around a pen, paper and...
Ganondorf most likely did it so link would collect the last stone. How else would link know to let a giant fish swallow him? Ganondorf can't just run over there and tell him, because then link might realize he's doing the VILLAIN a favor.
..And sorry if I'm forgetting something, but ruto was...