Mrs. Halibut is Gabby's mother.
Mrs. Halibut is a large purple fish with blonde hair, a pink dress, and a straw hat.
In all games, Gabby is trapped under a rock pile in a small cave. Mrs. Halibut attempts to help him, but she can't get inside because she is too big. After getting freed by Freddi Fish and Luther she asks for their help. After Freddi and Luther use a wooden board to pry the rock off and free Gabby, mother and son are reunited. As a reward for saving her son, Mrs. Halibut gives the duo a purple sea urchin before they leave.
Gabby and Mrs. Halibut are later shown as Freddi and Luther take Grandma Grouper's Kelp Treasure back to Grandma Grouper, only if the player has Freddi and Luther save Gabby. If not, the segment is skipped.