One of the fondest memories I have as child for Nowruz is getting the goldfish for our Haftsin. The goldfish and bowl of water represent movement and life. Goldfish is also the sign of the last month in Persian calendar (Esfand) and it turning around the bowl is a sign of turning and changing of the year. There are so many beautiful components of the Haftsin and each one of these elements symbolize a lovely concept and bring the newness of fresh life, just like the Earth which starts a new life by the arrival of spring.
To teach and learn more about the goldfish, the book "The New Year's Goldfish" written by Solmaz Parveen and illustrated by Tata Bobokhidze is great way to open the discussion of Nowruz tradition. As a family is busy preparing for the celebrations, the son Keyan could barely contain his excitement getting the gold fish.
To extend the story through a sensory bin you can let a child play with water, water beads, flat marbles, gold fish, fish bowls filled with water & liquid water colors. Through sensory play it will deepen their connection with components of the book, build their language and comprehension skills, and learn through play.