This is child-centered fiction. The adults don't get in the way (Dad, Librarian--and where was aquarium security? Quietly never pictured.), and Elliot moves forward assuming they won't--even though I was worried the entire time about when he would be found out. "Wild surprise ending"? No, a calm vindication of the story arc. This ending provided not only resolution to my worry, but also deconstructed it--a pleasant ending! And never a worry about there being a 'lesson' to be taught. Hmmm. I would love to see a moral at the end of this story!
The crayon line drawings were the distinctive style choice to complement ink drawings (reminiscent of Hilary Knight)--at their best when suggesting 'aquarium'.