This recipe for fish fumet is courtesy of chef Eric Ripert and used to make his Braised Halibut.
Soak fish bones in a bowl of lightly salted cold water for 1 hour, changing water twice as you soak. Drain bones and pat dry.
Preheat oven to 400 degrees. Transfer bones to a rimmed baking sheet and roast for 2 minutes. Carefully remove bones from pan and wipe away any blood.
Transfer bones to a stockpot and add 2 cups water; bring to a boil over high heat. Add shallots and wine; reduce heat to low and let simmer for 10 minutes. Remove from heat and let stand for 1 minute.
Strain liquid through a fine mesh sieve; discard solids. Let cool completely. Keep refrigerated up to 2 days or frozen up to 2 months.