Look closely

Ok I've watched this film about 20 times by now and I've noticed some big things that you haven't already knew.

Ok we know that Ponyo has a tone of magic inside of her due to the incident in her house so much so that she created a giant tsunami she was able to run on. Well when Ponyo makes Sosuke's Boat bigger near the end of the film they lift the boat up to take to the water, Ponyo runs into the water and you can see that she is walking on the water just like she did in the tsunami scene. But after taking a few steps on the water she suddenly sinks into he water, this foreshadows Ponyo's magic getting weaker.

Ok so when ever Ponyo is awake she has her up, but when she gets tired her hair is always lowered this foreshadows Ponyo running out of Magic.

When Ponyo and Sosuke help out the baby and make it two the woods you can see that Ponyo has gotten very tired and her hair is lowering and she even falls asleep only for a second as Sosuke wakes her up telling her that they need another candle. Ponyo falling asleep is showing that her magic is getting weaker and she is beginning to turn back into a fish but slowly. Then when she kneels down to the candle she says bye bye, and then the candle goes out. It's shown that Ponyo was using her magic to make the candle burn and she can't even keep the candle burning anymore. Also saying bye bye foreshadows her turning into a fish.

I write more later in the second part.