A nice little book for children. Nothing special per se, but I think the way life under water is portrayed is very well done. The smallest common issues are considered – where is the young waterman allowed to swim? Where’s home? How does he have to dress and what are his chores? This kind of attention to reality and detail is what I still love when reding sci-fi.
Another good children’s book by Otfried Preußler is The Little Ghost. If you’re looking for more serious books by him, Krabat is my favourite by far.