It could also be interpreted in a different way. Like the fact that the character Dori, who was somewhat flawed in that she had a short-term memory problem, was able to unite with Nemo's father, a character who had suffered the tremendous loss of having his son taken from him. She found a place of belonging. Also, Nemo, who was away from home, and in the fish tank in the dentist's office was able to find a place to belong among friends. (though it was only temporary).
well the term 'belonging' means one of two things:a close relationship or possessions (a person's belongings)...and if you are talking about the movie 'Finding Nemo', then it relates in which Nemo's father and him have a close bonding relationship and his father is very protective over him...i hope this helps some =]