The Red Fish, she appeared in the book One Fish Two Fish Red Fish Blue Fish.
In the Dr. Seuss Beginner Book Video intro, she appears as one of the characters that fly into their books. She appears as the first character out of the 12 Dr. Seuss Beginner Books. And she is the first character to get into her book. (The viewers see her --the Red Fish-- and she flies into her book titled One Fish Two Fish Red Fish Blue Fish.)
She (along with the Blue Fish) appear on pages 4 and 6. On page 6 --Beginner Book Video only-- she --along with the Blue, the Old, and the New Fish-- appear when Kay (as the narrator) recaps the previous fishes. That is, when she says, "Yes. Some are red and some are blue. Some are old, but some are new".
She appeared in the 2022 horror film The Mean One along with Blue Fish in a fishbowl at the hospital.