Actually, my current gf calls the clownfish Nemo 2 because of this funny story (my ex was not the sharpest pencil in the drawer):
I had gone away for the week with my ex and when we returned to my apartment she went over to the tank and says, "Where is Nemo? I don't see him."
The tank lights were off and I didn't really look so I say, "I am sure he is in there somewhere." I then look and realize that he really is missing and that my friend who was supposed to watch the tank hadn't done his job. Nemo had passed on to the big ocean in the sky. Being quick on my feet and knowing her intelligence level I immediately said, "Oh I bet he is just sleeping." Not knowing that fish don't take naps on the sand bed she said, Awwww.
Once she left, I ran to my LFS and got a new one and the ex was never the wiser even though Nemo 2 was noticably different in size and color. The current gf hates the ex so she calls the clownfish Nemo 2 to mock her.