How to Make It
In a large stockpot, heat the olive oil. Add the chopped onion, carrots and celery and cook over moderate heat, stirring occasionally, until the vegetables are golden, about 5 minutes. Add the fish bones and heads and cook until white, about 5 minutes. Stir in the white wine and cook for 1 minute. Stir in the ice and 8 cups of water and bring to a simmer. Cook over low heat until reduced by half, about 45 minutes. Strain the stock through a cheesecloth-lined sieve and keep warm.
On a work surface, using the side of a chef's knife, mash 3 of the anchovy fillets to a paste. In a large saucepan, cook the rice over moderately low heat, stirring, until translucent around the edges, about 5 minutes. Stir in the white wine and cook over moderate heat until absorbed, 1 minute. Add 1 cup of the warm stock and cook, stirring, until all of the stock is absorbed, about 3 minutes. Add another 1 cup of stock and the anchovy paste and cook, stirring, until the stock is absorbed, about 3 minutes. Repeat 5 more times with the remaining stock; cook until the rice is al dente and suspended in a creamy liquid (reserve any remaining stock for another use). Stir in the unsalted butter until the risotto is creamy. Remove from the heat and let stand for 2 minutes.
Stir in the salted butter and the colatura; season with salt. Spoon the risotto into bowls and garnish with the remaining anchovy fillets. Sprinkle with candied ginger and chives and serve.
Colatura is an Italian fish sauce made from anchovies. Look for it at specialty markets and on amazon.com.