Sheldon

Sheldon is an "H2O" intolerant seahorse who appears in the 2003 movie Finding Nemo.

Finding Nemo
One of Mr. Ray's students, Nemo meets Sheldon and his friends, Pearl and Tad, while waiting to start school. He was slapped and scolded by his father Bob for making fun of Nemo's small fin. He was also part of the group who saw the boat. Like the other children, he tries to see how close to it he can swim. When the diver appears, he flees with the rest of the class.

He briefly appears at the end welcoming Nemo and newcomer Squirt into the class.