H.A. and Margret Rey did not write or illustrate this book. It is one of the 2007 "New Adventures" and should not to be confused with Curious George Goes to the Aquarium (1984).
It gets an extra star because my toddler likes the book.
However, I think it is poorly written and the text sometimes does not match what is pictured.
For example, when George is pictured climbing a tree next to a wall, the book says he jumped over a gate. In another scene, George swings out over a tank of water in the penguin exhibit. The text says it is a "beluga tank". Beluga whales made an appearence earlier in the story but are not present in the scene.
While these faults may be minor, they stand out in a short book. I also think it shows a carelesss by the publisher.