When Chef Josh Niland was diagnosed at age eight with Wilms’ Tumor, a form of childhood cancer affecting the kidneys, he spent countless days in treatment and at home, where he got the taste for culinary pursuits in front of the television and its burgeoning programming of food shows. Today, he is one of Australia’s wunderkind with a successful Sydney restaurant where he practices fin-to-fin cooking. His book, “The Whole Fish Cookbook,” showcases every part of the animal.