I have mixed feelings about Disney films, but I thought we'd try it.
I researched and researched before I took my 5 y o to see Nemo. It was such a special day--me, daddy, and DS. I had been warned about the opening scene, so I had prepared DS. Well, he was scared the whole time & spent most of the movie hiding in my shoulder. Maybe seeing it on video isn't as bad, but he was SCARED and I don't blame him. THere were several scary scenes--I thought way worse than the mama getting eaten. The sharks, the jellyfish, etc. I felt like such a dope for taking him--but I thought I had done my homework.
He does not watch anything violent or scary, so I guess this was new to him. Actually, I take that back, he'd seen Toy Story & A Bug's Life, both of which had a couple quite scary scenes, but it was on a video & he was OK (we FF through them!).
FWIW, we did go see Brother Bear (I was way more prepared this time), and thought it was better. The violence wasn't nec. shown--more implied. Strangely, I thought in its way, it was more "gentle" than Nemo, but others may disagree.