1. The author of the English picture book about fish is Marcus Pfister.2. Marcus Pfister is the author of the English picture book about fish because he is a renowned Swiss author and illustrator known for his book "The Rainbow Fish," which tells the story of a beautiful fish with shimmering scales. He has written and illustrated many other books featuring fish as well.3. In addition to "The Rainbow Fish," Marcus Pfister has written and illustrated several other popular fish-themed picture books, such as "Rainbow Fish to the Rescue!" and "Hopper Hunts for Spring." His books are loved by children worldwide for their vibrant illustrations and engaging storytelling.