How to Make It
In a large saucepan, combine the chicken broth with the clam juice, orange juice, thyme and 1 tablespoon of the mint. Cover and bring to a boil, then reduce the heat to low and simmer for 10 minutes. Season the fish with salt and pepper and add to the pan. Cover and simmer gently for 4 minutes. Remove the pan from the heat and let the fish stand covered for 10 minutes, or until the fish starts to flake. Using a slotted spoon, transfer the fish to a plate and tent with foil to keep warm. Reserve the broth.
In a medium saucepan, melt the butter in the oil. Add the onion and garlic, season with salt and cook over moderate heat, stirring occasionally, until softened, about 10 minutes. Add the rice and cook, stirring, for 2 minutes. Stir in 1 cup of the hot broth and cook until almost evaporated, about 3 minutes. Add 1/2 cup of the broth and cook, stirring constantly, until absorbed, about 2 minutes. Continue stirring in the broth, 1/2 cup at a time, until it is almost absorbed. The risotto is done when the rice is al dente, about 20 minutes total. Stir in the peas, radishes and the remaining 1 tablespoon of mint.
Spoon the risotto into bowls and top with the fish. Season with salt, garnish with mint leaves and serve.