Mr. Grouper, the big yellow fish, is the Bubble Guppies' teacher in the Nickelodeon show for preschoolers, Bubble Guppies. While Mr. Grouper is very smart, he doesn't always know the answers to everything, so he encourages the Bubble Guppies to learn with him and find the answers in a variety of different ways. The best thing about Mr. Grouper, is that he makes learning fun.